@article {2369, title = {Long-chain rhenium and technetium glucosamine conjugates}, journal = {Dalton Transactions}, number = {42}, year = {2009}, note = {ISI Document Delivery No.: 508YBTimes Cited: 0Cited Reference Count: 44Bowen, Meryn L. Chen, Zhen-Feng Roos, Adrienne M. Misri, Ripen Haefeli, Urs Adam, Michael J. Orvig, Chris}, pages = {9228-9236}, type = {Article}, abstract = {A series of five glucosamine-conjugated organometallic complexes of the tricarbonyl cores of technetium-99m and rhenium were made. Glucosamine was derivatized at the C-2 nitrogen with long chain alkyl spacers linked to either pyridyl-tert-nitrogen-phenol tridentate chelates or cyclopentadienyl ligating groups. The metal complexes of the tridentate ligands were formed by refluxing with [Re(CO)(3)(H2O)(3)]Br, or with a base and [Tc-99m(CO)(3)(H2O)(3)](+). These ligands were found to be competent chelates in binding the [Tc-99m(CO)(3)](+) core as radiolabeling yields ranged from 87 to 93\% and the resulting complexes are stable to cysteine and histidine challenges for 24 h. The cyclopentadienyl analogues were formed using a double ligand transfer reaction for the rhenium complexes and a single ligand transfer for the technetium-99m complexes. All five rhenium complexes were tested as substrates of hexokinase; two of these complexes were tested as hexokinase inhibitors and they were found to be competent inhibitors, suggesting that they may be able to interact with hexokinase. MTT cytotoxicity studies were performed and the complexes tested were found to be non-toxic to the concentrations tested (100 mu M or 1 mM). GLUT-1 mediated cell uptake studies were performed on all five technetium-99m complexes, and their cell entry was found to parallel their lipophilicities, suggesting that cellular uptake is by passive diffusion and is not mediated by GLUT-1.}, keywords = {99M-TECHNETIUM, BIOMOLECULES, BREAST-CANCER, DERIVATIVES, HEXOKINASE, IN-VITRO, METAL-COMPLEXES, RE, TC-99M, TRANSPORT}, isbn = {1477-9226}, url = {://000270973800021}, author = {Bowen, M. L. and Chen, Z. F. and Roos, A. M. and Misri, R. and Hafeli, U. and Adam,Michael J. and Orvig, Chris} } @article {2369, title = {Long-chain rhenium and technetium glucosamine conjugates}, journal = {Dalton Transactions}, number = {42}, year = {2009}, note = {ISI Document Delivery No.: 508YBTimes Cited: 0Cited Reference Count: 44Bowen, Meryn L. Chen, Zhen-Feng Roos, Adrienne M. Misri, Ripen Haefeli, Urs Adam, Michael J. Orvig, Chris}, pages = {9228-9236}, type = {Article}, abstract = {A series of five glucosamine-conjugated organometallic complexes of the tricarbonyl cores of technetium-99m and rhenium were made. Glucosamine was derivatized at the C-2 nitrogen with long chain alkyl spacers linked to either pyridyl-tert-nitrogen-phenol tridentate chelates or cyclopentadienyl ligating groups. The metal complexes of the tridentate ligands were formed by refluxing with [Re(CO)(3)(H2O)(3)]Br, or with a base and [Tc-99m(CO)(3)(H2O)(3)](+). These ligands were found to be competent chelates in binding the [Tc-99m(CO)(3)](+) core as radiolabeling yields ranged from 87 to 93\% and the resulting complexes are stable to cysteine and histidine challenges for 24 h. The cyclopentadienyl analogues were formed using a double ligand transfer reaction for the rhenium complexes and a single ligand transfer for the technetium-99m complexes. All five rhenium complexes were tested as substrates of hexokinase; two of these complexes were tested as hexokinase inhibitors and they were found to be competent inhibitors, suggesting that they may be able to interact with hexokinase. MTT cytotoxicity studies were performed and the complexes tested were found to be non-toxic to the concentrations tested (100 mu M or 1 mM). GLUT-1 mediated cell uptake studies were performed on all five technetium-99m complexes, and their cell entry was found to parallel their lipophilicities, suggesting that cellular uptake is by passive diffusion and is not mediated by GLUT-1.}, keywords = {99M-TECHNETIUM, BIOMOLECULES, BREAST-CANCER, DERIVATIVES, HEXOKINASE, IN-VITRO, METAL-COMPLEXES, RE, TC-99M, TRANSPORT}, isbn = {1477-9226}, url = {://000270973800021}, author = {Bowen, M. L. and Chen, Z. F. and Roos, A. M. and Misri, R. and Hafeli, U. and Adam,Michael J. and Orvig, Chris} } @article {2502, title = {Near-Infrared Absorbing Azo Dyes: Synthesis and X-ray Crystallographic and Spectral Characterization of Monoazopyrroles, Bisazopyrroles, and a Boron-Azopyrrole Complex}, journal = {Journal of Organic Chemistry}, volume = {74}, number = {15}, year = {2009}, note = {ISI Document Delivery No.: 476XOTimes Cited: 5Cited Reference Count: 69Li, Yan Patrick, Brian O. Dolphin, David}, month = {Aug}, pages = {5237-5243}, type = {Article}, abstract = {Symmetric 2,5-bisazopyrroles 2(a-d) were synthesized by a one-step reaction of substituted phenyl diazonium salts [R{\textquoteright}(Ph)N2+Cl-] [a, R{\textquoteright}= 4-N(CH3)(2); b, R{\textquoteright} = 2OH; c, R{\textquoteright} = 2-CO2H; d, R{\textquoteright} = 4-NO2] with pyrrole under basic conditions. Asymmetric 2,5-bisazopyrroles 3(a-d) were synthesized by reacting substituted phenyl diazonium salts [R {\textquoteright}{\textquoteright}(Ph)N2+Cl-] (a, R {\textquoteright}{\textquoteright} = 4-OCH3; b, R {\textquoteright}{\textquoteright} = H; c, R {\textquoteright}{\textquoteright} = 4-Br; d, R {\textquoteright}{\textquoteright} = 4-NO2) with 2-(4-dimethylaminophenylazo)-1H-pyrrole (1a) under the same conditions. The reactions of 2a with boron trifluoride and iodomethane provided a BF2-azopyrrole complex of 1H-pyrrolo[2,1-c]-1,2,4,5-boratriazole (4) and 2,5-bisazo-1-methylpyrrole 5. X-ray crystallographic and spectral analysis of la, 2a, 2b, and 4 showed that la has three crystal forms: 1a(I), 1a(II), and 1a(III), the latter two bearing a bicyclic ring system formed via intermolecular hydrogen bonding. Complex 4 was found to be the most planar due to a rigid trans-azo configuration and has the longest N=N bond distances (1.322 and 1.300 angstrom) and wavelength of maximum absorption (754 nm). The N=N bond distances increase in the sequence of monoazopyrrole [1a(1): 1,253 angstrom], bisazopyrrole (2a: 1.283 angstrom), bisazopyrrole with intramolecular hydrogen bonding (2b: 1,293 and 1.293 angstrom), and the BF2-azopyrrole complex. Their maximum absorptions shift bathochromically in the sequence of monoazopyrrole (1a: 443 nm), bisazopyrroles [2(a-d), 3(a-d), 5: 486-615 nm), and the BF2-azopyrrole complex. These results are important for the design of near-infrared absorbing azo dyes and suggest an efficient path for the preparation of near-infrared absorbing azo dyes by effectively enhancing pi-electron delocalization.}, keywords = {C-13 NMR, CI-DISPERSE-ORANGE-29, CRYSTAL-STRUCTURE, DERIVATIVES, DISAZO DYES, HETEROCYCLIC DIAZO COMPONENTS, INTRAMOLECULAR PROTON-TRANSFER, NONLINEARITIES, optical, PHOTODYNAMIC THERAPY, SOLID-STATE}, isbn = {0022-3263}, url = {://000268480300014}, author = {Li, Y. and Patrick, B. O. and Dolphin, D.} } @article {2507, title = {Regioselective Reduction of 2,4-Diacylpyrroles and the Synthesis of a 2,4-Divinylpyrrole}, journal = {European Journal of Organic Chemistry}, number = {21}, year = {2009}, note = {ISI Document Delivery No.: 478ASTimes Cited: 0Cited Reference Count: 18Lin, Yan Dolphin, David}, month = {Jul}, pages = {3562-3566}, type = {Article}, abstract = {Reduction of 2,4-diacylpyrroles followed by dehydration to prepare the divinylpyrroles has been studied. The N-phenylsulfonyl group exhibited directing ability at the 4-position during the reduction of 2,4-diacylpyrrole and complete regioselectivity was achieved for formations of the 2- and 4-carbinols; several new derivatives, including 2,4-divinylpyrrole, have been prepared. ((C) Wiley-VCH Verlag GmbH \& Co. KGaA, 69451 Weinheim, Germany, 2009)}, keywords = {DERIVATIVES, N Heterocycles, porphyrins, PYRROLES, QUARARIBEA METABOLITES, REDUCTION, regioselectivity, SUBSTITUENTS}, isbn = {1434-193X}, url = {://000268560700010}, author = {Lin, Y. and Dolphin, D.} } @article {2589, title = {Synthetic Studies toward Sordarin: Building Blocks for the Terpenoid Core and for Analogues Thereof}, journal = {Journal of Organic Chemistry}, volume = {74}, number = {4}, year = {2009}, note = {ISI Document Delivery No.: 406TATimes Cited: 2Cited Reference Count: 73Schule, Arnaud Liang, Huan Vors, Jean-Pierre Ciufolini, Marco A.}, month = {Feb}, pages = {1587-1597}, type = {Article}, abstract = {Avenues to bi- and tricyclic building blocks for the elaboration of sordaricin and its analogues are described. The target molecules were obtained through inter- and intramolecular Diels-Alder reactions of a number of previously unknown cyclopentadienes. Unusual properties of 3-cyanoenones and 1-cyanocyclopentadienes have been unveiled and circumvented.}, keywords = {ANTIFUNGAL SORDARINS, BAYLIS-HILLMAN REACTION, DERIVATIVES, ELONGATION-FACTOR 2, ENOLATE FORMATION, FUNGAL PROTEIN-SYNTHESIS, KETONE ENOLIZATION, LITHIUM DIALKYLAMIDES, RING-CLOSURE, SODIUM-BOROHYDRIDE}, isbn = {0022-3263}, url = {://000263316600020}, author = {Schule, A. and Liang, H. and Vors, J. P. and Ciufolini,Marco A.} } @article {2013, title = {G(boolean AND)C quartet - A DNA-inspired Janus-GC heterocycle: Synthesis, structural analysis, and self-organization}, journal = {Journal of the American Chemical Society}, volume = {130}, number = {39}, year = {2008}, note = {ISI Document Delivery No.: 353GITimes Cited: 7Cited Reference Count: 32Asadi, Ali Patrick, Brian O. Perrin, David M.}, month = {Oct}, pages = {12860-+}, type = {Article}, abstract = {In this communication we disclose the synthesis and characterization of a DNA-inspired self-complementary heterocycle that contains AAD-DAA H-bond acceptor/donor patterns. Whereas in the past such AAD-DAA self-complementarity has given rise to trimeric and hexameric rosettes, we now demonstrate that the same H-bonding scheme, when properly arrayed, can be used to program a tetrameric rosette, which unlike a G-quartet requires no metal binding or peripheral components for p reorganization. Of note, we exploit both 2D-NOESY and DOSY H-1 NMR to substantiate the tetrameric stoichiometry in this noncovalent rosette comprising 12 H-bonds.}, keywords = {BASE, CHEMISTRY, COMPLEXES, DERIVATIVES, FOLIC-ACID SALTS, HELICAL ROSETTE NANOTUBES, HYDROGEN-BONDED NETWORKS, MOLECULAR TECTONICS, RECOGNITION, solid-state structures}, isbn = {0002-7863}, url = {://000259553700012}, author = {Asadi, A. and Patrick, B. O. and Perrin,David M.} } @article {2159, title = {Improved procedure for the bimolecular oxidative amidation of phenols}, journal = {Journal of Organic Chemistry}, volume = {73}, number = {11}, year = {2008}, note = {ISI Document Delivery No.: 307MRTimes Cited: 17Cited Reference Count: 24Liang, Huan Ciufolini, Marco A.}, month = {Jun}, pages = {4299-4301}, type = {Article}, abstract = {Trifluoroacetic acid (TFA) is an effective promoter of the bimolecular Ritter-like oxidative amidation of 4-substituted phenols induced by PhI(OAc)(2) in MeCN. This suppresses the need for fluoroalcohol cosolvents, increases the yields, and facilitates isolation/purification procedures.}, keywords = {DERIVATIVES, ETHERS, FR901483, HYPERVALENT IODINE OXIDATION, lactones, REAGENTS, SPIROLEUCETTADINE}, isbn = {0022-3263}, url = {://000256323500050}, author = {Liang, H. and Ciufolini,Marco A.} } @article {2092, title = {Mechanistic Studies on N-Acetylmuramic Acid 6-Phosphate Hydrolase (MurQ): An Etherase Involved in Peptidoglycan Recycling}, journal = {Biochemistry}, volume = {47}, number = {44}, year = {2008}, note = {ISI Document Delivery No.: 366TUTimes Cited: 4Cited Reference Count: 37Hadi, Timin Dahl, Ulrike Mayer, Christoph Tanner, Martin E.}, month = {Nov}, pages = {11547-11558}, type = {Article}, abstract = {Peptidoglycan recycling is a process in which bacteria import cell wall degradation products and incorporate them back into either peptidoglycan biosynthesis or basic metabolic pathways. The enzyme MurQ is an N-acetylmuramic acid 6-phosphate (MurNAc 6-phosphate) hydrolase (or etherase) that hydrolyzes the lactyl side chain from MurNAc 6-phosphate and generates GlcNAc 6-phosphate. This study supports a mechanism involving the syn elimination of lactate to give an alpha,beta-unsaturated aldehyde with (E)-stereochemistry, followed by the syn addition of water to give product. The observation of both a kinetic isotope effect slowing the reaction of [2-H-2]MurNAc 6-phosphate and the incorporation of solvent-derived deuterium into C2 of the product indicates that the C2-H bond is cleaved during catalysis. The observation that the solvent-derived 180 isotope is incorporated into the C3 position of the product, but not the C1 position, provides evidence of the cleavage of the C3-O bond and argues against imine formation. The finding that 3-chloro-3-deoxy-GlcNAc 6-phosphate serves as an alternate substrate is also consistent with an elimination-addition mechanism. Upon extended incubations of MurQ with GlcNAc 6-phosphate, the alpha,beta-unsaturated aldehydic intermediate accumulates in solution, and H-1 NMR analysis indicates it exists as the ring-closed form of the (E)-alkene. A structural model is developed for the Escherichia coli MurQ and is compared to that of the structural homologue glucosamine-6-phosphate synthase. Putative active site acid/base residues are probed by mutagenesis, and Glu83 and Glu114 are found to be crucial for catalysis. The Glu83Ala mutant is essentially inactive as an etherase yet is capable of exchanging the C2 proton of substrate with solvent-derived deuterium. This suggests that Glu83 may function as the acidic residue that protonates the departing lactate.}, keywords = {CATALYSIS, CELL-WALL, COLI GLUCOSAMINE-6-PHOSPHATE SYNTHASE, DERIVATIVES, ELIMINATION, ENOYL-COA HYDRATASE, ENVIRONMENT, ESCHERICHIA-COLI, INHIBITION, PHOSPHATE}, isbn = {0006-2960}, url = {://000260507100019}, author = {Hadi, T. and Dahl, U. and Mayer, C. and Tanner, M. E.} } @article {2137, title = {Synthesis and Enzymatic Incorporation of Modified Deoxyadenosine Triphosphates}, journal = {European Journal of Organic Chemistry}, number = {29}, year = {2008}, note = {ISI Document Delivery No.: 365YXTimes Cited: 7Cited Reference Count: 35Lam, Curtis Hipolito, Christopher Perrin, David M.}, month = {Oct}, pages = {4915-4923}, type = {Article}, abstract = {Several deoxyadenosine triphosphates containing modifications at the 8-position have been synthesized. Suitably protected 8-bromodeoxyadenosines were coupled with five imidazole-containing moieties by nucleophilic aromatic substitution or Sonagashira coupling to give modified nucleosides that were then triphosphorylated. Incorporation assays were performed for these modified residues with many commercially available DNA polymerases, and it was found that two of the modified dATPs could be effectively taken up as substrates by Sequenase V2.0. These two residues are candidates for substrates in combinatorial selections in the search for improved catalysis from DNAzymes. ((C) Wiley-VCH Verlag GmbH \& Co. KGaA, 69451 Weinheim, Germany, 2008)}, keywords = {AMINO-ACID, bioorganic chemistry, CATALYTIC REPERTOIRE, CLEAVING DNA ENZYME, DERIVATIVES, DNA, ENZYMES, FUNCTIONALITIES, HETEROCYCLES, IN-VITRO SELECTION, NUCLEIC-ACIDS, nucleotides, OLIGONUCLEOTIDES, PCR, POLYMERASES, SELEX}, isbn = {1434-193X}, url = {://000260447200009}, author = {Lam, C. and Hipolito, C. and Perrin,David M.} } @article {2205, title = {Template-assembled synthetic G-quartets (TASQs)}, journal = {Angewandte Chemie-International Edition}, volume = {47}, number = {26}, year = {2008}, note = {ISI Document Delivery No.: 317SSTimes Cited: 8Cited Reference Count: 38Nikan, Mehran Sherman, John C.}, pages = {4900-4902}, type = {Article}, keywords = {cation, CAVITANDS, CHEMISTRY, DEOXYGUANOSINE, DERIVATIVES, G-quartets, GUANOSINE, HOST-GUEST COMPLEXATION, NUCLEOSIDES, NUCLEOTIDE, ORGANIC-SOLVENTS, QUADRUPLEX STRUCTURE, supramolecular, supramolecular chemistry, SYNTHESIS, TELOMERIC DNA OLIGONUCLEOTIDES, TEMPLATE}, isbn = {1433-7851}, url = {://000257040800022}, author = {Nikan, M. and Sherman, J. C.} } @article {1392, title = {Glucosamine conjugates of tricarbonylcyclopentadienyl rhenium(I) and technetium(I) cores}, journal = {Inorganic Chemistry}, volume = {45}, number = {17}, year = {2006}, note = {ISI Document Delivery No.: 073DPTimes Cited: 13Cited Reference Count: 43Ferreira, Cara L. Ewart, Charles B. Bayly, Simon R. Patrick, Brian O. Steele, Jennifer Adam, Michael J. Orvig, Chris}, month = {Aug}, pages = {6979-6987}, type = {Article}, abstract = {To obtain a Tc-99m glucose conjugate for imaging, double-ligand transfer (DLT) and related reactions were examined for the preparation of CpM(CO)(3) (Cp = cyclopentadienyl; M = Re, Tc) complexes with pendant carbohydrates at Cp. Tricarbonyl {N-(1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-beta-D-glucopyranose) cyclopentadienyl carboxamide} rhenium(I) (1a) and tricarbonyl {N-(2-amino-2-deoxy-beta-D-glucopyranose) cyclopentadienyl carboxamide} rhenium(I) (2a) were prepared. The compounds were fully characterized by mass spectrometry, elemental analysis, IR, and NMR spectroscopy. Full assignment of the NMR spectra verified the pendant nature of the glucosamine moieties in the solution state and that 2a exists as both anomers. The solid-state structure of 2a was determined by X-ray crystallography, again confirming the pendant nature of the glucosamine, but differing from the solution state in that the, anomer crystallized preferentially (93\%). Compound 2a was determined to be a high-affinity competitive inhibitor (K-i = 330 +/- 70 mu M) of the glucose metabolism enzyme hexokinase, demonstrating that it retains certain biological activity. The Tc-99m analogues 1b and 2b were prepared in moderate radiochemical yields by means of the single-ligand transfer (SLT) route, which is more pertinent to radiopharmaceutical synthesis.}, keywords = {BIOMOLECULES, COORDINATION, CYCLOPENTADIENYL-TRICARBONYL COMPLEXES, DERIVATIVES, FUNCTIONALIZATION, IN-VITRO, METAL-COMPLEXES, RE-186(I), RECEPTOR, TC-99M}, isbn = {0020-1669}, url = {://000239723300060}, author = {Ferreira, C. L. and Ewart, C. B. and Bayly, S. R. and Patrick, B. O. and Steele, J. and Adam,Michael J. and Orvig, Chris} } @article {1392, title = {Glucosamine conjugates of tricarbonylcyclopentadienyl rhenium(I) and technetium(I) cores}, journal = {Inorganic Chemistry}, volume = {45}, number = {17}, year = {2006}, note = {ISI Document Delivery No.: 073DPTimes Cited: 13Cited Reference Count: 43Ferreira, Cara L. Ewart, Charles B. Bayly, Simon R. Patrick, Brian O. Steele, Jennifer Adam, Michael J. Orvig, Chris}, month = {Aug}, pages = {6979-6987}, type = {Article}, abstract = {To obtain a Tc-99m glucose conjugate for imaging, double-ligand transfer (DLT) and related reactions were examined for the preparation of CpM(CO)(3) (Cp = cyclopentadienyl; M = Re, Tc) complexes with pendant carbohydrates at Cp. Tricarbonyl {N-(1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-beta-D-glucopyranose) cyclopentadienyl carboxamide} rhenium(I) (1a) and tricarbonyl {N-(2-amino-2-deoxy-beta-D-glucopyranose) cyclopentadienyl carboxamide} rhenium(I) (2a) were prepared. The compounds were fully characterized by mass spectrometry, elemental analysis, IR, and NMR spectroscopy. Full assignment of the NMR spectra verified the pendant nature of the glucosamine moieties in the solution state and that 2a exists as both anomers. The solid-state structure of 2a was determined by X-ray crystallography, again confirming the pendant nature of the glucosamine, but differing from the solution state in that the, anomer crystallized preferentially (93\%). Compound 2a was determined to be a high-affinity competitive inhibitor (K-i = 330 +/- 70 mu M) of the glucose metabolism enzyme hexokinase, demonstrating that it retains certain biological activity. The Tc-99m analogues 1b and 2b were prepared in moderate radiochemical yields by means of the single-ligand transfer (SLT) route, which is more pertinent to radiopharmaceutical synthesis.}, keywords = {BIOMOLECULES, COORDINATION, CYCLOPENTADIENYL-TRICARBONYL COMPLEXES, DERIVATIVES, FUNCTIONALIZATION, IN-VITRO, METAL-COMPLEXES, RE-186(I), RECEPTOR, TC-99M}, isbn = {0020-1669}, url = {://000239723300060}, author = {Ferreira, C. L. and Ewart, C. B. and Bayly, S. R. and Patrick, B. O. and Steele, J. and Adam,Michael J. and Orvig, Chris} } @article {1499, title = {New oligophosphines and (hydroxymethyl)phosphonium chlorides}, journal = {Inorganic Chemistry}, volume = {45}, number = {7}, year = {2006}, note = {ISI Document Delivery No.: 028HCTimes Cited: 6Cited Reference Count: 46}, month = {Apr}, pages = {2917-2924}, type = {Article}, abstract = {{The new oligophosphines [H2P(CH2)(2)](2)PH, [H2P(CH2)(2)P(H)CH2](2), and {[(H2P(CH2)(2)](2)PCH2}(2) have been made by hydrophosphination of diethyl vinylphosphonate (2) with H2P(CH2)(2)PH2 (1), using different ratios of 2/1, followed by LiAlH4 reduction of the phosphonate intermediates; the three phosphonate precursors were obtained as oils of varying purity (similar to 90-95\%) in low (similar to 20\%) to almost quantitative yield. The tri-, tetra-, and hexaphosphines were then treated with formaldehyde in the presence of hydrochloric acid to generate the corresponding water-soluble (hydroxymethyl)phosphonium chlorides {(HOCH2)(3)P[(CH2)(2)P(CH2OH)(2)](n)(CH2)(2)P(CH2PH)(3)}Cl-m (n = 1}, keywords = {ALDEHYDES, BRIGHTNESS STABILIZING AGENTS, COMPLEXES, CRYSTAL-STRUCTURE, DERIVATIVES, FORMALDEHYDE, LIGANDS, phosphines, SALTS, WATER}, isbn = {0020-1669}, url = {://000236476700018}, author = {Moiseev, D. and James, Brian R. and Patrick, B. O. and Hu, Thomas Q.} } @article {1499, title = {New oligophosphines and (hydroxymethyl)phosphonium chlorides}, journal = {Inorganic Chemistry}, volume = {45}, number = {7}, year = {2006}, note = {ISI Document Delivery No.: 028HCTimes Cited: 6Cited Reference Count: 46}, month = {Apr}, pages = {2917-2924}, type = {Article}, abstract = {{The new oligophosphines [H2P(CH2)(2)](2)PH, [H2P(CH2)(2)P(H)CH2](2), and {[(H2P(CH2)(2)](2)PCH2}(2) have been made by hydrophosphination of diethyl vinylphosphonate (2) with H2P(CH2)(2)PH2 (1), using different ratios of 2/1, followed by LiAlH4 reduction of the phosphonate intermediates; the three phosphonate precursors were obtained as oils of varying purity (similar to 90-95\%) in low (similar to 20\%) to almost quantitative yield. The tri-, tetra-, and hexaphosphines were then treated with formaldehyde in the presence of hydrochloric acid to generate the corresponding water-soluble (hydroxymethyl)phosphonium chlorides {(HOCH2)(3)P[(CH2)(2)P(CH2OH)(2)](n)(CH2)(2)P(CH2PH)(3)}Cl-m (n = 1}, keywords = {ALDEHYDES, BRIGHTNESS STABILIZING AGENTS, COMPLEXES, CRYSTAL-STRUCTURE, DERIVATIVES, FORMALDEHYDE, LIGANDS, phosphines, SALTS, WATER}, isbn = {0020-1669}, url = {://000236476700018}, author = {Moiseev, D. and James, Brian R. and Patrick, B. O. and Hu, Thomas Q.} } @article {1411, title = {Pyrrole synthesis catalyzed by AgOTf or cationic Au(I) complexes}, journal = {Journal of Organic Chemistry}, volume = {71}, number = {12}, year = {2006}, note = {ISI Document Delivery No.: 049PTTimes Cited: 65Cited Reference Count: 71Harrison, Tyler J. Kozak, Jennifer A. Corbella-Pane, Montserrat Dake, Gregory R.}, month = {Jun}, pages = {4525-4529}, type = {Article}, abstract = {Either silver trifluoromethanesulfonate or a mixture of gold( I) chloride, silver trifluoromethanesulfonate, and triphenylphosphine catalyze the formation of pyrroles from substituted beta-alkynyl ketones and amines. The reactions proceed by using 5 mol \% of catalyst with yields of isolated pyrroles ranging from 13\% to 92\%. Sixteen examples are used to compare the effectiveness of each catalyst.}, keywords = {2-PROPYNYL-1, 3-DICARBONYL COMPOUNDS, AMINATION/ANNULATION REACTIONS, C-H BONDS, CARBOXYLIC-ACIDS, DERIVATIVES, EFFICIENT SYNTHESIS, FURANS, ONE-POT, PYRROLES, REGIOSELECTIVE SYNTHESIS, SUBSTITUTED}, isbn = {0022-3263}, url = {://000238029300023}, author = {Harrison, T. J. and Kozak, J. A. and Corbella-Pane, M. and Dake, G. R.} } @article {1240, title = {Coordination chemistry of P,O-bidentate phosphinophenolates with Ga3+ and In3+}, journal = {Dalton Transactions}, number = {13}, year = {2005}, note = {ISI Document Delivery No.: 936NJTimes Cited: 4Cited Reference Count: 63}, pages = {2268-2274}, type = {Article}, abstract = {Novel complexes of Ga3+ and In3+ were synthesized with two hetero donor phosphinophenolate ligands (PO-, ortho-phenoxydiphenylphosphine; MePO-, 5-methyl-2-phenoxydiphenylphosphine). RPO- (R = H, Me) binds in a bidentate fashion through both the hard O and the soft P donor atoms to In3+, whereas, it only binds Ga3+ through the O donor. Electrochemical synthesis proved to be a practical synthetic approach to In-2(PO)(3)Cl-3, In(PO)(3) and In(MePO)(3). [In(MePO)(H2O)Cl-2](2) and Ga(HPO)Cl-3 were synthesized from MCl3 (M = In and Ga, respectively). Both dimetallic indium complexes, [In(MePO)(H2O)Cl-2](2) and In-2(PO)(3)Cl-3, incorporate phenolate oxygen atoms bridging the two metal ions. Each pair of In atoms are in a distorted octahedral geometry in each complex, with the former complex having a coordination sphere of PO3Cl2 for both indium metal ions and the latter showing a coordination sphere of PO3Cl2 for one indium and P2O3Cl for the other. Ga(HPO)Cl-3 is a zwitterionic complex, with Ga having a OCl3 coordination core. All these complexes were fully characterized by a variety of techniques including X-ray crystallography.}, keywords = {aluminum, CRYSTAL, DERIVATIVES, gallium, INDIUM TRICHLORIDE, LIGANDS, METAL CHELATE COMPLEXES, MOLECULAR-STRUCTURE, phosphine, THALLIUM}, isbn = {1477-9226}, url = {://000229862400008}, author = {Saatchi, K. and Patrick, B. O. and Orvig, Chris} } @article {1278, title = {Estimation of Hammett sigma constants of substituted benzenes through accurate density-functional calculation of core-electron binding energy shifts}, journal = {International Journal of Quantum Chemistry}, volume = {103}, number = {5}, year = {2005}, note = {ISI Document Delivery No.: 929WJTimes Cited: 16Cited Reference Count: 1212th Brazilian Symposium of Theoretical ChemistryNOV 23-26, 2003Caxambu, BRAZIL}, month = {Jun}, pages = {509-515}, type = {Proceedings Paper}, abstract = {For substituted benzenes such as (p-F-C6H4-Z), Linderberg et al. [1] demonstrated the validity of an equation similar to: Delta CEBE approximate to K sigma, where Delta CEBE is the difference in core-electron binding energies (CEBEs) of the fluorinated carbon in p-F-C,H,-Z and that in FC6H5, the parameter K a function of the type of reaction, and sigma is the Hammett substituent (sigma) constant. In this work, CEBEs of ring carbon atoms for a series of para disubstituted molecules p-F-C,H,-Z were first calculated using Density Functional Theory (DFT) with the scheme Delta E-ks (PW86-PW91)/TZP+C-rel//HF/6-31G*. An average absolute deviation of 0.13 eV from experiment was obtained for the CEBEs. Then we performed a linear regression analysis in the form of Y = A+B*X for a plot of Hammett up constants against calculated shifts Delta CEBEs (in eV) for the fluorinated carbon. The results were: A = -0.08 and B = 1.01, with correlation coefficient R = 0.973, standard deviation = 0.12, and P < 0.0001. The intercept A of the fitted line, close to zero, shows that the Hammett sigma(p) constant is proportional to the calculated Delta CEBES. On the other hand, the slope B of the straight line gives an estimate of the parameter K. Similar statistical correlations were obtained for the carbon atoms ortho and meta to the substituent Z. (c) 2005 Wiley Periodicals, Inc.}, keywords = {DCEBE, DERIVATIVES, DFT, disubstitued benzenes FC(6)H(4)Z, Hammett sigma-constant}, isbn = {0020-7608}, url = {://000229377000005}, author = {Takahata, Y. and Chong, D. P.} } @article {1195, title = {High yielding synthesis of 3a-hydroxypyrrolo[2,3-b]indoline dipeptide methyl esters: Synthons for expedient introduction of the hydroxypyrroloindoline moiety into larger peptide-based natural products and for the creation of tryptathionine bridges}, journal = {Journal of Organic Chemistry}, volume = {70}, number = {21}, year = {2005}, note = {ISI Document Delivery No.: 971SRTimes Cited: 12Cited Reference Count: 33}, month = {Oct}, pages = {8424-8430}, type = {Article}, abstract = {This work describes a rapid and high yielding oxidation of 14 tryptophanylated amino acid methyl esters to the corresponding 3 alpha-hydroxypyrrolo[2,3-b]indoline (Hpi) amino acids with generally facile separation of syn-cis and anti-cis diastereomers. Structural X-ray diffraction data are presented for both diastereomers of Tr-Hpi-Gly-OMe, which allow for a putative assignment of the other 13 pairs of diastereomers reported herein, based on correlations with H-1 NMR chemical shifts. Selective and high yielding deprotection at either the N or C terminus is described, allowing the Hpi motif to be introduced efficiently into potential targets with minimal protecting group manipulation. Two tripeptides containing Hpi and cysteine were prepared and treated with acid in the Savige-Fontana reaction to produce a cyclic tryptathionine linkage, characteristic of both amatoxins and phallotoxins.}, keywords = {ANALOGS, ASYMMETRIC EPOXIDATION METHOD, CONFIGURATION, CONFORMATION, CYCLIZATION, CYSTEINE SULFHYDRYL-GROUPS, DERIVATIVES, HIMASTATIN, OXYGENATION, TRYPTOPHAN}, isbn = {0022-3263}, url = {://000232405500022}, author = {May, J. P. and Fournier, P. and Pellicelli, J. and Patrick, B. O. and Perrin,David M.} } @article {1070, title = {Nitrogenous educts through oxidative amidation of phenols: The bimolecular reaction}, journal = {Organic Letters}, volume = {7}, number = {2}, year = {2005}, note = {ISI Document Delivery No.: 887UFTimes Cited: 34Cited Reference Count: 29}, month = {Jan}, pages = {175-177}, type = {Article}, abstract = {The elusive oxidative amidation of phenols to 4-aza-substituted dienones in the bimolecular mode may be achieved by treatment with iodobenzene diacetate ("DIB") in a mixture of hexafluoro-2-propanol and acetonitrile.}, keywords = {(-)-TAN1251A, AMIDES, AMINATION, ARENES, CYCLIZATION, DERIVATIVES, FR901483, HYPERVALENT IODINE OXIDATION, N-ACYLNITRENIUM IONS, TYROSINE}, isbn = {1523-7060}, url = {://000226330300003}, author = {Canesi, S. and Bouchu, D. and Ciufolini,Marco A.} } @article {1143, title = {Platinum(II) and palladium(II) complexes of bisphosphine ligands bearing o-N,N-dimethylanilinyl substituents: A hint of catalytic olefin hydration}, journal = {Inorganic Chemistry}, volume = {44}, number = {9}, year = {2005}, note = {ISI Document Delivery No.: 922CLTimes Cited: 9Cited Reference Count: 55}, month = {May}, pages = {3290-3298}, type = {Article}, abstract = {Platinum(II) and palladium(II) complexes of the potentially hexadentate P,N-donor ligand family Ar2P-X-PAr2 (X = (CH2)(2) [dmape], cyclic-C5H8 [dmapcp]; Ar = o-NN-dimethylanilinyl) are described. In CH2Cl2, the dmape complexes exist as equilibrium mixtures of MCl2(P,P{\textquoteright}-dmape) and [MCl(P, P, N-dmape)]Cl isomers (M = Pd, Pt), governed by Delta H degrees = -19 +/- 4 U mol(-1) and Delta S degrees = -100 +/- 30 J mol(-1) K-1 for M = Pt, and Delta H degrees = -11 +/- 7 U mol-1 and Delta S degrees = -60 +/- 20 J mol-1 K-1 for M = Pd. The water-soluble dmapcp complexes exist solely in the [MCl(P,P{\textquoteright},N-dmapcp)]Cl form, but the free and coordinated anilinyl rings in these complexes are in slow diastereoselective exchange, X-ray crystal structures for MCl2(P,P{\textquoteright}-dmape) (M = Pd, Pt), and the [PdCl(P,P{\textquoteright},N-dmape)](+) and [PtCl-P,P{\textquoteright},N-dmapcp)](+) cations, are presented. Some of the complexes show marginal activity in water for the catalyzed hydration of maleic to malic acid, giving about 6-7\% conversion in 24 h at 100 degrees C and substrate: catalyst loadings of 100:1. Attempts to synthesize a PdCl(P,P{\textquoteright},N-dmapm)(+) species led instead to isolation of [Pd(mu-Cl)(P,P-dmapm)](2)-[PF6](2) (dmapm = Ar2PCH2Ar2).}, keywords = {2-PYRIDYLPHOSPHINE LIGANDS, COORDINATION CHEMISTRY, CRYSTAL-STRUCTURE, DERIVATIVES, DONOR GROUPS, HYDROGENATION, RHODIUM COMPLEXES, RUTHENIUM(II), TERTIARY PHOSPHINES, WATER-SOLUBLE PHOSPHINES}, isbn = {0020-1669}, url = {://000228813400045}, author = {Jones, N. D. and Meessen, P. and Losehand, U. and Patrick, B. O. and James, Brian R.} } @article {1230, title = {Separation of porphyrin-based photosensitizer isomers by laser-induced fluorescence capillary electrophoresis}, journal = {Electrophoresis}, volume = {26}, number = {20}, year = {2005}, note = {ISI Document Delivery No.: 982VMTimes Cited: 3Cited Reference Count: 43}, month = {Oct}, pages = {3861-3868}, type = {Article}, abstract = {Methods for the separation of photosensitizer isomers, such as benzoporphyrin derivative monoacid, benzoporphyrin ethyl monoacid, 2-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a, diethyleneglycol diester benzoporphyrin derivative, tin ethyl etiopurpurin, and phthalocyanine tetrasulfonate, have been systematically developed by CE. Detection was accomplished by UV absorption at 214 nm or by LIF with excitation at 442/488 nm and emission at 690 nm. The effects of three major experimental parameters of buffer types, organic solvents, and surfactant additives are described. The optimized separation conditions were determined so as to provide satisfactory separation efficiency and analysis time. The methods are shown to be suitable for the separation and determination of porphyrin and phthalocyanines regioisomers, diastereoisomers, and enantiomers.}, keywords = {chiral additives, CHLORIN, DERIVATIVES, EFFICACY, ENANTIOMERS, FLUORESCENCE DETECTION, FRACTION, LIGHT, PANCREATIC-CANCER CELLS, PERFORMANCE LIQUID-CHROMATOGRAPHY, pharmacokinetics, PHOTODYNAMIC THERAPY, PHTHALOCYANINES, porphyrins, regioisomers}, isbn = {0173-0835}, url = {://000233189700008}, author = {Peng, X. J. and Sternberg, E. and Dolphin, D.} } @article {1204, title = {Synthesis and characterization of dual function vanadyl, gallium and indium curcumin complexes for medicinal applications}, journal = {Journal of Inorganic Biochemistry}, volume = {99}, number = {11}, year = {2005}, note = {ISI Document Delivery No.: 984RUTimes Cited: 22Cited Reference Count: 41}, month = {Nov}, pages = {2217-2225}, type = {Article}, abstract = {Novel bis[4-hydroxy-3-methoxyphenyl]-1,6-heptadiene-3,5-dione (curcumin) complexes with the formula, ML3, where M is Ga(III) or In(III), or of the formula, ML2 where M is [Vo](2+), have been synthesized and characterized by mass spectrometry, infrared and absorption spectroscopies, and elemental analysis. A new ligand, bis[4-acetyl-3-hydroxyphenyl]-1,6-heptadiene-3,5-dione (diacetylbisdemethoxycurcumin, DABC) was similarly characterized; an X-ray structure analysis was performed. Vanadyl complexes tested in an acute i.p. testing protocol in STZ-diabetic rats showed a lack of insulin enhancing potential. Vanadyl complexes were, however, more cytotoxic than were the ligands alone in standard MTT (3-[4,5-dimethylthiazole-2-yl]ate, -2.5-diphenyl-tetrazolium bromide) cytotoxicity testing, using mouse lymphoma cells. With the exception of DABC, that was not different from VO(DABC)(2), the complexes were not significantly different from one another, with IC50 values in the 5-10 mu M range. Gallium and indium curcumin complexes had IC50 values in the same 5-10 mu M range; whereas Ga(DAC)(3) and In(DAC)(3) (where DAC = diacetylcurcumin) were much less cytotoxiC (IC50 = 20-30 mu M). Antioxidant capacity was decreased in VO(DAC)(2), Ga(DAC)(3), and In(DAC)(3),, compared to vanadyl, gallium and indium curcumin, corroborating the importance of curcumin{\textquoteright}s free phenolic OH groups for scavenging oxidants, and correlated with reduced cytotoxic potential. (c) 2005 Elsevier Inc. All rights reserved.}, keywords = {ANALOGS, antioxidant capacity, ANTIOXIDANT MECHANISM, ANTITUMOR ACTIVITY, BINDING, COORDINATION CHEMISTRY, curcumin, cytotoxicity, DERIVATIVES, diacetylcurcumin, gallium, GROUP, indium, INSULIN MIMICS, MANGANESE COMPLEXES, RADICAL SCAVENGING ABILITY, TOXICITY, VANADIUM}, isbn = {0162-0134}, url = {://000233322800012}, author = {Mohammadi, K. and Thompson, K. H. and Patrick, B. O. and Storr, T. and Martins, C. and Polishchuk, E. and Yuen, V. G. and McNeill, J. H. and Orvig, Chris} } @article {928, title = {Cross-metathesis reactions of vinyl-chlorins and -porphyrins catalyzed by a "second generation" Grubbs{\textquoteright} catalyst}, journal = {Chemical Communications}, number = {7}, year = {2004}, note = {ISI Document Delivery No.: 816QLTimes Cited: 13Cited Reference Count: 26}, month = {Apr}, pages = {852-853}, type = {Article}, abstract = {The first application of olefin cross-metathesis with vinyl-chlorins and vinylporphyrins using a "second generation" Grubbs{\textquoteright} catalyst is reported. Cross-metathesis products were obtained in good yields with high E-stereoselectivity.}, keywords = {COMPLEXES, DERIVATIVES, OLEFIN METATHESIS, POLYMERIZATION, RUCL2(=CHR)(PR(3))(2), SCHROCK CATALYST}, isbn = {1359-7345}, url = {://000221124300061}, author = {Liu, X. and Sternberg, E. and Dolphin, D.} } @article {843, title = {Nucleophilic additions of lactam-derived enol triflates to aldehydes mediated by nickel(II) and chromium(II) salts}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {82}, number = {2}, year = {2004}, note = {ISI Document Delivery No.: 802BHTimes Cited: 5Cited Reference Count: 39}, month = {Feb}, pages = {139-144}, type = {Article}, abstract = {Enol trifluoromethanesulfonates (triflates) derived from N-protected lactams undergo nickel(II)-chloride- and chromium(II)-chloride-promoted carbonyl additions to aldehydes. The yields of this process range from 42\%-84\%.}, keywords = {BOND FORMATIONS, BREVETOXIN-B, carbonyl addition, CATALYSIS, chromium(II) chloride, CONSTRUCTION, CYCLIZATION, DERIVATIVES, DYNEMICIN-A, ENANTIOSELECTIVE, lactam-derived enol triflate, LEPADIN B, NI(II)/CR(II)-MEDIATED COUPLING REACTION, nickel(II) chloride, TOTAL-SYNTHESIS}, isbn = {0008-4042}, url = {://000220138500010}, author = {Easton, L. P. and Dake, G. R.} } @article {879, title = {Reactivity of (trimpsi)V(NO)X-2 complexes (X = Cl, Br, I; trimpsi = (BuSi)-Bu-t(CH2PMe2)(3)). Synthesis of the first group 5 alkyl nitrosyls}, journal = {Organometallics}, volume = {23}, number = {4}, year = {2004}, note = {ISI Document Delivery No.: 772ZFTimes Cited: 4Cited Reference Count: 40}, month = {Feb}, pages = {657-664}, type = {Article}, abstract = {Treatment of (trimpsi)V(NO)Cl-2 (trimpsi = (BuSi)-Bu-t(CH2PMe2)(3)) in NEt3 with 2 equiv each of p-toluic acid and Proton Sponge affords lemon yellow (trimpsi)V(NO)(eta(1)-O2C-4-C6H4Me)(2) (1) in 47\% isolated yield. Similarly, reaction of (trimpsi)V(NO)Cl-2 with 2 equiv of AgOTf in CH2Cl2 provides lemon yellow (trimpsi)V(NO)(OTf)(2) (2) in a comparable yield. Alternatively, 2 can be obtained directly in 40\% yield by treating CH2Cl2 solutions of (trimpsi)V(CO)(2)(NO) at -60 degreesC with 2 equiv of AgOTf. Likewise, both benzoyl peroxide and diphenyl disulfide are capable of oxidizing (trimpsi)V(CO)(2)(NO) under similar conditions to form (trimpsi)V(NO)X-2-type complexes, namely (trimpsi)V(NO)(O2CPh)(2) (3) and (trimpsi)V(NO)(SPh)(2) (4), respectively. The reactions of (trimpsi)V(NO)X-2 (X = Cl, Br) with Mg(CH2SiMe3)(2)(.)x(dioxane) (either 0.5 equiv or an excess) in THF afford the orange-red alkyl complexes (trimpsi)V(NO)(CH2SiMe3)X (X = Cl (5), Br (6)) in reasonable yields. Other members of this family of complexes such as (trimpsi)V(NO)(CH2CMe3)Cl (7) and (trimpsi)V(NO)(Me)Cl (8) can also be obtained by employing similar metathetical methodology, but all attempts to synthesize (trimpsi)V(NO)(alkyl)2 complexes have to date been unsuccessful. All new complexes have been fully characterized by standard methods, and the solid-state molecular structures of 1(.)1.5C(6)H(5)Me and 5(.)2C(4)H(8)O have been established by single-crystal X-ray diffraction analyses.}, keywords = {CHEMISTRY, CP{\textquoteright}M(NO)R2, CRYSTAL-STRUCTURES, DERIVATIVES, H BOND ACTIVATION, MOLYBDENUM, THERMAL-ACTIVATION, TUNGSTEN, V METAL-CARBONYLS, VANADIUM}, isbn = {0276-7333}, url = {://000188872700007}, author = {Hayton, T. W. and Patrick, B. O. and Legzdins,Peter} } @article {922, title = {Scandium-catalyzed intramolecular hydroamination. Development of a highly active cationic catalyst}, journal = {Organometallics}, volume = {23}, number = {10}, year = {2004}, note = {ISI Document Delivery No.: 818FNTimes Cited: 100Cited Reference Count: 37}, month = {May}, pages = {2234-2237}, type = {Article}, abstract = {The scandium-catalyzed intramolecular hydroamination of alkynes and alkenes is reported. Complex structure/catalyst activity investigations resulted in the identification of a highly catalytically active cationic, beta-diketiminato scandium complex.}, keywords = {ALKENES, ALKYNES, AMIDO COMPLEXES, BETA-DIKETIMINATO LIGANDS, DERIVATIVES, GROUP-3 METALS, ORGANOSCANDIUM, REACTIVITY, YTTRIUM, ZIRCONIUM}, isbn = {0276-7333}, url = {://000221231100006}, author = {Lauterwasser, F. and Hayes, P. G. and Brase, S. and Piers, W. E. and Schafer, L. L.} } @article {880, title = {The solid-state molecular structure of W(NO)(3)Cl-3 and the nature of its W-NO bonding}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {82}, number = {2}, year = {2004}, note = {ISI Document Delivery No.: 802BHTimes Cited: 1Cited Reference Count: 46}, month = {Feb}, pages = {285-292}, type = {Article}, abstract = {{The monomeric trinitrosyl complex, W(NO)(3)Cl-3, can be prepared by the treatment of WCl6 in CH2Cl2 with NO gas, and its identity has been unambiguously confirmed by a single-crystal X-ray diffraction analysis. The complex crystallizes in the space group Pmn2(1) as a three-component twin (a = 10.4280(4) Angstrom}, keywords = {bonding, CARBONYL, CHEMISTRY, CRYSTAL-STRUCTURE, DERIVATIVES, DICHLORODINITROSYLTUNGSTEN, DICHLOROTRINITROSYLVANADIUM, MOLYBDENUM, MONONUCLEAR, NITROSYL, NITROSYL COMPLEXES, STRUCTURE, TUNGSTEN}, isbn = {0008-4042}, url = {://000220138500024}, author = {Hayton, T. W. and Patrick, B. O. and Legzdins,Peter and McNeil, W. S.} } @article {616, title = {Reduction of hafnium(IV) complexes in the presence of molecular nitrogen: Attempts to form dinitrogen complexes of the heaviest group 4 element}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {81}, number = {11}, year = {2003}, note = {ISI Document Delivery No.: 746YXTimes Cited: 10Cited Reference Count: 28}, month = {Nov}, pages = {1376-1387}, type = {Article}, abstract = {The reaction of [P2N2]Li-2(dioxane)(2) with HfCl4(THF)(2) (where [P2N2] = PhP(CH2SiMe2NSiMe2CH2)(2)PPh) results in the formation of the hafnium dichloride complex [P2N2]HfCl2 (1). The behaviour of 1 as a potential precursor in the generation of a dinitrogen coordination complex is described. Reduction of 1 with potassium-graphite (C8K), under dinitrogen, under a variety of conditions led to a number of products, one of which is the dinuclear derivative with bridging P-phenyl groups that has the general formula {[P2N2]Hf}(2) (2). Reduction of the hafnium diiodide [P2N2]HfI2 (3) - prepared via the reaction of 1 with excess Me3SiI - with C8K results in the formation of ([P2N2]Hf)(2)(mu-eta(2):eta(2)-N-2) (4) as the major product of the reaction, while {[P2N2]Hf}(2) (2) and [P2N2]Hf(C7H8) (5) appear to be minor products. Reaction of 1 with 2 equiv of MeMgCl gives [P2N2]HfMe2 (6), which, upon exposure to an atmosphere of H-2, gives the hafnium tetrahydride {[P2N2]Hf}(2)(m-H)(4) (7).}, keywords = {COORDINATION CHEMISTRY, DERIVATIVES, DINITROGEN, donor ligands, FLUXIONAL BEHAVIOR, hafnium, hydride, macrocycle, mixed, {ALKYL}, isbn = {0008-4042}, url = {://000186777600031}, author = {Fryzuk,Michael D. and Corkin, J. R. and Patrick, B. O.} } @article {742, title = {Vanadyl-thiazolidinedione combination agents for diabetes therapy}, journal = {Bioconjugate Chemistry}, volume = {14}, number = {1}, year = {2003}, note = {ISI Document Delivery No.: 637YYTimes Cited: 23Cited Reference Count: 42}, month = {Jan-Feb}, pages = {212-221}, type = {Article}, abstract = {A series of vanadium compounds, chelated by ligands containing a thiazolidinedione moiety as an additional insulin-enhancing component, were produced in this study to create potentially synergistic compounds. A set of four bifunctional ligand precursors were synthesized: (+/-)-5-4-[(5-hydroxy-4-oxo-4H-pyran-2-ylmethyl)amino]benzylthiazolidi ne-2,4-dione (HL1), (+/-)-5-4-[5-hydroxy-1-methyl-4-oxo-1,4-dihydro-pyridin-2-ylmethyl)amin o]benzylthiazolidine-2,4-dione (HL2) 5-[4-(5-hydroxy-4-oxo-4H-pyran-2-ylmethoxy)benzylidenelthiazolidine-2,4- dione (HL1), and (+/-)-5-4-(5-hydroxy-4-oxo-4H-pyran-2-ylmethoxy)benzyl]thiazolidine-2,4 -dione (HL4), each containing a metal chelating portion as well as a thiazolidinedione moiety. From this set of ligand precursors, air-stable VO(L-1)(2), VO(L-3)(2), and VO(L-4)(2) were prepared. The four ligand precursors and three complexes were tested for insulin-enhancing potential in STZ-diabetic rats and compared to rosiglitazone and BMOV, respectively. Both the ligand precursors HL1 and HL3 showed enhanced activity compared with that of rosiglitazone. The complex VO(L-3)(2) showed the most efficacious hypoglycemic effects in this study; however, neither additive nor synergistic effects were observed using this acute animal model.}, keywords = {AGENT, ANTIHYPERGLYCEMIC, BIOLOGICAL-ACTIVITY, BIS(MALTOLATO)OXOVANADIUM(IV), BLOOD-GLUCOSE, COMPLEXES, DERIVATIVES, GLUCOSE-LOWERING PROPERTIES, INSULIN MIMETIC AGENT, RAT ADIPOCYTES, TROGLITAZONE}, isbn = {1043-1802}, url = {://000180542400025}, author = {Storr, T. and Mitchell, D. and Buglyo, P. and Thompson, K. H. and Yuen, V. G. and McNeill, J. H. and Orvig, Chris} } @article {408, title = {Bisphosphine ligands containing two o-N,N-dimethylanilinyl substituents at each phosphorus atom}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {80}, number = {11}, year = {2002}, note = {ISI Document Delivery No.: 623LDTimes Cited: 11Cited Reference Count: 35}, month = {Nov}, pages = {1600-1606}, type = {Article}, abstract = {The synthesis and complete characterization of the family of tetra(amine)bisphosphine ligands (o-NMe2C6H4)(2)P-(X)-P(o-NMe2C6H4)(2), where X = CH2 (dmapm), (CH2)(2) (dmape), and CH(CH2)(3)CH (dmapcp), are described. Crystal structure data are compared with known, analogous bisphosphines containing o-pyridyl or phenyl substituents in place of the o-dimethylanilinyl groups. Several short, intramolecular C-H...N distances in the anilinyl derivatives may represent the presence of weak hydrogen bonds.}, keywords = {ACID, amine, AMPHIPHILIC DIPHOSPHINES, CATALYTIC-HYDROGENATION, CHEMISTRY, DERIVATIVES, HYDROFORMYLATION, hydrogen-bonding to N atoms, phosphine, polydentate, RESOLUTION, RHODIUM COMPLEXES, RUTHENIUM(II), WATER-SOLUBLE PHOSPHINES}, isbn = {0008-4042}, url = {://000179703800030}, author = {Jones, N. D. and Meessen, P. and Smith, M. B. and Losehand, U. and Rettig, S. J. and Patrick, B. O. and James, Brian R.} } @article {435, title = {Evaluation of tetraphenyl-2,3-dihydroxychlorins as potential photosensitizers}, journal = {Journal of Porphyrins and Phthalocyanines}, volume = {6}, number = {2}, year = {2002}, note = {ISI Document Delivery No.: 595XYTimes Cited: 15Cited Reference Count: 33}, pages = {146-155}, type = {Article}, abstract = {A series of beta,beta-dihydroxychlorins derived from meso-tetraphenylporphyrins (TPPs) have been synthesized. Their in vitro cytotoxicity has been measured and compared to BPDMA (verteporfin). Under the assay conditions BPDMA had an LD50 (lethal dose to kill 50\% of cells) value of 0.007 muM (5 ng/mL). The LD50 values for the TPP derivatives varied from 1.7 x 10(-2) to 9.9 muM depending upon the substituents and their position on the phenyl groups. One example of the dihydroxychlorin prepared from unsubstituted 5,15-diphenylporphyrin was examined and this exhibited an LD50 of 2.4 x 10(-3) muM! Copyright (C) 2002 Society of Porphyrins \& Phthalocyanines.}, keywords = {AGGREGATION, BACTERIOCHLORINS, beta, beta-dihydroxychlorins, BIODISTRIBUTION, chlorins, cytotoxicity, DERIVATIVES, photodynamic, PHOTODYNAMIC THERAPY, PHOTOPHYSICAL PROPERTIES, PHOTOSENSITIZERS, porphyrins, PROTEIN-BINDING, SENSITIZERS, therapy, TUMOR PHOTOSENSITIZERS}, isbn = {1088-4246}, url = {://000178134600008}, author = {Macalpine, J. K. and Boch, R. and Dolphin, D.} } @article {343, title = {Fast, efficient syntheses of linear poly(dipyrromethene)s}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {80}, number = {12}, year = {2002}, note = {ISI Document Delivery No.: 633ZKTimes Cited: 11Cited Reference Count: 44}, month = {Dec}, pages = {1668-1675}, type = {Article}, abstract = {The synthesis of three octapyrrolic, 8-10, and four dodecapyrrolic, 15-18, oligomers is reported. They are linear poly(dipyrromethene)s and potential ligands as building blocks for supramolecular architectures through self-assembly. Octapyrrolic oligomers 8-10 were prepared in 90-95\% yields by condensation of 2 equiv of a tripyrrolic compound 4 with 1 equiv of diformyldipyrrolic compounds 5-7. A similar procedure, involving the condensation of 2 equiv of a pentapyrrolic starting material 13 with 1 equiv of 5-7 or 14, was found to give rise to the corresponding dodecameric systems 15-18 in 41-56\% yields.}, keywords = {ANALOG, ARCHITECTURE, BILIRUBIN, CHEMISTRY, CU-I, DERIVATIVES, dipyrromethane, dipyrromethene, DIPYRROMETHENE LIGANDS, LEAD(II) COMPLEXES, linear polypyrroles, poly(dipyrromethene), PYRROLE PIGMENTS, TRANSPORT}, isbn = {0008-4042}, url = {://000180314900007}, author = {Chen, Q. Q. and Dolphin, D.} } @article {429, title = {Incorporation of 8-histaminyldeoxyadenosine [8-(2-(4-imidazolyl)ethylamino)-2 {\textquoteright}-deoxyriboadenosine] into oligodeoxyribonucleotides by solid phase phosphoramidite coupling}, journal = {Nucleosides Nucleotides \& Nucleic Acids}, volume = {21}, number = {10}, year = {2002}, note = {ISI Document Delivery No.: 622CATimes Cited: 5Cited Reference Count: 37}, pages = {651-664}, type = {Article}, abstract = {The 3{\textquoteright} phosphoramidite of 8-histaminyl deoxyadenosine has been prepared and successfully incorporated into a short oligodeoxyribonucleotide. The synthetic methodology leading to this preparation is given and the implications for developing new DNAzymes as well as probing unusual nucleic acid structures are discussed.}, keywords = {BEARING IMIDAZOLE, CATALYTIC REPERTOIRE, CLEAVAGE, DERIVATIVES, DNA, IMIDAZOLYL FUNCTIONALITIES, NUCLEIC-ACIDS, OLIGONUCLEOTIDES, RIBONUCLEASES, RNA}, isbn = {1525-7770}, url = {://000179627900003}, author = {Lermer, L. and Hobbs, J. and Perrin,David M.} } @article {379, title = {Phosphorus phenyl-group activation by reduced zirconium and niobium complexes stabilized by the [P2N2] macrocycle}, journal = {Journal of the American Chemical Society}, volume = {124}, number = {4}, year = {2002}, note = {ISI Document Delivery No.: 514THTimes Cited: 21Cited Reference Count: 23}, month = {Jan}, pages = {516-517}, type = {Article}, keywords = {ARENE COMPLEX, CHEMISTRY, CRYSTAL, DERIVATIVES, DINITROGEN, LIGAND, REACTIVITY, TITANIUM}, isbn = {0002-7863}, url = {://000173456800002}, author = {Fryzuk,Michael D. and Kozak, C. M. and Mehrkhodavandi, Parisa and Morello, L. and Patrick, B. O. and Rettig, S. J.} } @article {510, title = {Synthesis and solution studies of the complexes of trivalent lanthanides with the tetraazamacrocycle TETA-(PO)(2)}, journal = {Inorganic Chemistry}, volume = {41}, number = {4}, year = {2002}, note = {ISI Document Delivery No.: 524GATimes Cited: 9Cited Reference Count: 29}, month = {Feb}, pages = {685-692}, type = {Article}, abstract = {A new potentially multidentate hexaprotic ligand H-6[TETA-(PO)(2)] has been prepared by reaction of ethylenediamine-N,N{\textquoteright}-diacetic acid (EDDA), paraformaldehyde, and phosphinic acid; its coordination properties with three lanthanide ions (La3+, Gd3+, and Lu3+) have been explored. The structures of the complexes were studied in aqueous solution by potentiometric pH titrations and by P-31 NMR spectroscopy. Four acidity constants were determined potentiometrically in the range 2.5 < pH < 14. The four measured pK(a) values can be divided into two groups, and within each group the initial deprotonation was found to have little effect on the second. Variable temperature 31P and P-31{H-1} EXSY NMR spectra showed that, for [Lu(TETA-(PO)(2))](3-), the two phosphorus atoms exist in different chemical environments and undergo an exchange process which is very fast on the NMR time scale at room temperature. This result is consistent with one of the phosphinate residues coordinating the metal ion and exchanging with a free analogue. In the case of [La(TETA-(PO)(2))](3-), only one temperature invariant signal is observed in P-31 NMR spectra; it corresponds to both phosphinate residues remaining uncoordinated to La3+. The stability of [Ln-(TETA-(PO)(2))](3-) has an order of La3+ > Gd3+ > Lu3+. The coordination of one phosphinate residue to Lu3+ brings the metal ion closer to the plane of four nitrogens and farther from the four carboxylate arms, resulting in [Lu(TETA-(PO)(2))](3-) having a lower stability than the corresponding La3+ and Gd3+ complexes. A pM-pH distribution diagram showed that introducing two phosphinate groups into TETA renders [Gd(TETA-(PO)(2))](3-) more stable than [Gd(TETA)](-). The selectivity factor of the ligand for Gd3+ vs Ca2+, Zn2+, and Cu2+ has been calculated, and the hydration number for [Dy(TETA-(PO)(2))](3-) has been measured by O-17 NMR spectroscopy to be zero.}, keywords = {ACID, CRYSTAL-STRUCTURE, DERIVATIVES, DOTA, DYNAMICS, IONS, LIGANDS, luminescence, STABILITIES}, isbn = {0020-1669}, url = {://000174003700014}, author = {Song, B. and Storr, T. and Liu, S. and Orvig, Chris} } @article {392, title = {Synthesis, characterization, and solution redox properties of (trimpsi)M(CO)(2)(NO) complexes [M = V, Nb, Ta; trimpsi = (BuSi)-Bu-t(CH2PMe2)(3)]}, journal = {Inorganic Chemistry}, volume = {41}, number = {16}, year = {2002}, note = {ISI Document Delivery No.: 582RTTimes Cited: 7Cited Reference Count: 85}, month = {Aug}, pages = {4114-4126}, type = {Article}, abstract = {{Treatment of [Et4N][M(CO)(6)] (M = Nb, Ta) with I-2 in DME at -78 degreesC produces solutions of the bimetallic anions [M-2(mu-l)(3)(CO)(8)](-). Addition of the tripodal phosphine (BuSi)-Bu-t(CH2PMe2)(3) (trimpsi) followed by refluxing affords (trimpsi)M(CO)(3)I [M = Nb (1), Ta (2)], which are isolable in good yields as air-stable, orange-red microcrystalline solids. Reduction of these complexes with 2 equiv of Na/Hg, followed by treatment with Diazald in THF, results in the formation of (trimpsi)M(CO)(2)(NO) [M = Nb (3), Ta (4)] in high isolated yields. The congeneric vanadium complex, (trimpsi)V(CO)(2)(NO) (5), can be prepared by reacting [Et4N][V(CO)(6)] with [NO][BF4] in CH2Cl2 to form V(CO)(5)(NO). These solutions are treated with 1 equiv of trimpsi to obtain (eta(2)-trimpsi)V(CO)(3)(NO). Refluxing orange THF solutions of this material affords 5 in moderate yields. Reaction of (trimpsi)VCl3(THF) (6) with 4 equiv of sodium naphthalenide in THF in the presence of excess CO provides [Et4N][(trimpsi)V(CO)(3)] (7), (trimpsi)V(CO)(3)H, and [(trimpsi)V(mu-Cl)(3)V(trimpsi)][(eta(2)-trimpsi)V(CO)(4)].3THF ([8][9].3THF). All new complexes have been characterized by conventional spectroscopic methods, and the solid-state molecular structures of 2.(1)/2THF, 3-5, and [8][9].3THF have been established by X-ray diffraction analyses. The solution redox properties of 3-5 have also been investigated by cyclic voltammetry. Cyclic voltammograms of 3 and 4 both exhibit an irreversible oxidation feature in CH2Cl2 (E-p}, keywords = {CHARACTERIZATION, CHEMISTRY, DERIVATIVES, HIGHLY REDUCED ORGANOMETALLICS, ISOCYANIDE COMPLEXES, NITRIC-OXIDE, PHOSPHINE COMPLEXES, RAY CRYSTAL-STRUCTURES, SPECTROSCOPIC, tantalum, VANADIUM(II)}, isbn = {0020-1669}, url = {://000177365500013}, author = {Hayton, T. W. and Daff, P. J. and Legzdins,Peter and Rettig, S. J. and Patrick, B. O.} } @article {374, title = {Tris(trifluoromethyl)borane carbonyl, (CF3)(3)BCO - Synthesis, physical, chemical and spectroscopic properties, gas phase, and solid state structure}, journal = {Journal of the American Chemical Society}, volume = {124}, number = {51}, year = {2002}, note = {ISI Document Delivery No.: 628QATimes Cited: 49Cited Reference Count: 86}, month = {Dec}, pages = {15385-15398}, type = {Article}, abstract = {Tris(trifluoromethyl)borane carbonyl, (CF3)(3)BCO, is obtained in high yield by the solvolysis of K[B(CF3)(4)] in concentrated sulfuric acid. The in situ hydrolysis of a single bonded CF3 group is found to be a simple, unprecedented route to a new borane carbonyl. The related, thermally unstable borane carbonyl, (C6F5)(3)BCO, is synthesized for comparison purposes by the isolation of (C6F5)(3)B in a matrix of solid CO at 16 K and subsequent evaporation of excess CO at 40 K. The colorless liquid and vapor of (CF3)3BCO decomposes slowly at room temperature. In the gas phase t(1/2) is found to be 45 min. In the presence of a large excess of (CO)-C-13, the carbonyl substituent at boron undergoes exchange, which follows a first-order rate law. Its temperature dependence yields an activation energy (EA) of 112 kJ mol(-1). Low-pressure flash thermolysis of (CF3)3BCO with subsequent isolation of the products in low-temperature matrixes, indicates a lower thermal stability of the (CF3)3B fragment, than is found for (CF3)3BCO. Toward nucleophiles (CF3)3BCO reacts in two different ways: Depending on the nucleophilicity of the reagent and the stability of the adducts formed, nucleophilic substitution of CO or nucleophilic addition to the C atom of the carbonyl group are observed. A number of examples for both reaction types are presented in an overview. The molecular structure of (CF3)(3)BCO in the gas phase is obtained by a combined microwave-electron diffraction analysis and in the solid state by single-crystal X-ray diffraction. The molecule possesses C3 symmetry, since the three CF3 groups are rotated off the two possible positions required for C3, symmetry. All bond parameters, determined in the gas phase or in the solid state, are within their standard deviations in fair agreement, except for internuclear distances most noticeably the B-CO bond lengths, which is 1.69(2) Angstrom in the solid state and 1.617(12) Angstrom in the gas phase. A corresponding shift of nu(CO) from 2267 cm(-1) in the solid state to 2251 cm-1 in the gas phase is noted in the vibrational spectra. The structural and vibrational study is supported by DFT calculations, which provide, in addition to the equilibrium structure, confirmation of experimental vibrational wavenumbers, IR-band intensities, atomic charge distribution, the dipole moment, the B-CO bond energy, and energies for the elimination of CF2 from (CF3)(x)BF3-x1 = 1-3. In the vibrational analysis 21 of the expected 26 fundamentals are observed experimentally. The B-11-, C-13-, and F-19-NMR data, as well as the structural parameters of (CF3)(3)BCO, are compared with those of related compounds.}, keywords = {= F, COMPLEXES, CRYSTAL, DERIVATIVES, IR, MICROWAVE-SPECTRUM, MOLECULAR-STRUCTURES, NMR, UNDECAFLUORODIANTIMONATE(V), X-RAY-DIFFRACTION}, isbn = {0002-7863}, url = {://000180006600046}, author = {Finze, M. and Bernhardt, E. and Terheiden, A. and Berkei, M. and Willner, H. and Christen, D. and Oberhammer, H. and Aubke, F.} } @article {5102, title = {Bis(mercapto) and hydrido(thiolate) complexes of Ru(II)-dppm (dppm = Ph2PCH2PPh2)}, journal = {Inorganica Chimica Acta}, volume = {320}, number = {1-2}, year = {2001}, note = {ISI Document Delivery No.: 472CETimes Cited: 6Cited Reference Count: 33}, month = {Aug}, pages = {184-189}, type = {Article}, abstract = {From a mixture of cis- and trans-Ru(SH)(2)(dppm)(2) (4), formed from reaction of H2S with trans-Ru(H)Cl(dppm)(2) (2), a crystal of cis-4 has been isolated and its structure determined by X-ray analysis. The mercapto protons are located within the centrosymmetric structure, although the S-atoms are partially disordered (S - H similar to 1.06 Angstrom). The thiolate complexes, trans-Ru(H)SR(dppm)(2) (R = Ph, 5a; C6F5, 5b), have been isolated from reaction of trans-2 with 1 equiv. of RSH. trans-Ru(H)SH(dppm)(2) (3) has been isolated from reaction of H2S with a mixture of cis- and trans-Ru(H)(2)(dppm)(2) (1). An improved synthetic route for 1 is presented. (C) 2001 Elsevier Science B.V. All rights reserved.}, keywords = {CHEMISTRY, COMPLEXES, crystal structures, CRYSTAL-STRUCTURE, DERIVATIVES, DINUCLEAR RHODIUM COMPLEXES, hydrido complexes, HYDROFORMYLATION, MECHANISMS, MERCAPTO, PHOSPHINE COMPLEXES, ruthenium complexes, RUTHENIUM(II), THIOLATO, WATER}, isbn = {0020-1693}, url = {://000170965000025}, author = {Khorasani-Motlagh, M. and Safari, N. and Pamplin, C. B. and Patrick, B. O. and James, Brian R.} } @article {5161, title = {Bridging the gap between proteins and nucleic acids: A metal-independent RNAseA mimic with two protein-like functionalities}, journal = {Journal of the American Chemical Society}, volume = {123}, number = {8}, year = {2001}, note = {ISI Document Delivery No.: 405LXTimes Cited: 74Cited Reference Count: 49}, month = {Feb}, pages = {1556-1563}, type = {Article}, abstract = {Two synthetically modified nucleoside triphosphate analogues (adenosine modified with an imidazole and uridine modified with a cationic amine) are enzymatically polymerized in tandem along a degenerate DNA library for the combinatorial selection of an RNAse A mimic. The selected activity is consistent with both electrostatic and general acid/base catalysis at physiological pH in the absence of divalent metal cations. The simultaneous use of two modified nucleotides to enrich the catalytic repertoire of DNA-based catalysts has never before been demonstrated and evidence of general acid/base catalysis at pH 7.4 for a DNAzyme has never been previously observed in the absence of a divalent metal cation or added cofactor, This work illustrates how the incorporation of protein-like functionalities in nucleic acids can bridge the gap between proteins and oligonucleotides underscoring the potential for using nucleic acid scaffolds in the development of new materials and improved catalysts for use in chemistry and medicine.}, keywords = {5{\textquoteright}-TRIPHOSPHATES, ADENOSINE, ANALOG, CATALYSIS, CLEAVAGE, CLEAVING DNA ENZYME, DERIVATIVES, IN-VITRO SELECTION, PHOSPHORYL-TRANSFER-REACTIONS, PORPHYRIN METALATION, TRANSITION-STATE}, isbn = {0002-7863}, url = {://000167162100002}, author = {Perrin,David M. and Garestier, T. and Helene, C.} } @article {5073, title = {Formation and reactivity of the zirconium ethylene complexes [eta(5)-C5H3-1,3-(SiMe2CH2PR2)(2)]Zr(eta(2)-CH2=CH2)(X) (R = Me, Pr (i); X = Br, C5H5)}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {79}, number = {5-6}, year = {2001}, note = {ISI Document Delivery No.: 456EVTimes Cited: 5Cited Reference Count: 36}, month = {May}, pages = {536-545}, type = {Article}, abstract = {{The formation and reactivity of the zirconium ethylene complexes (R)[P2Cp]Zr(eta (2)-CH2=CH2)(X) (2a: R = Pr-i}, keywords = {ALKENE, ALKYNE, CARBONYL, CHEMISTRY, CRYSTAL-STRUCTURE, cyclopentadienyl phosphine, DERIVATIVES, LIGANDS, metallocyclopropane, metals, NORBORNENE, SIME3, TITANIUM, ZIRCONIUM}, isbn = {0008-4042}, url = {://000170070900011}, author = {Fryzuk,Michael D. and Duval, P. B. and Rettig, S. J.} } @article {5233, title = {Lanthanide chemistry with bis{[bis(carboxymethyl)amino]methyl}phosphinate: What does an extra phosphinate group do to EDTA?}, journal = {Inorganic Chemistry}, volume = {40}, number = {15}, year = {2001}, note = {ISI Document Delivery No.: 452MHTimes Cited: 9Cited Reference Count: 34}, month = {Jul}, pages = {3734-3738}, type = {Article}, abstract = {H5XT (bis{[bis(carboxymethyl)amino]methyl}phosphinic acid) is an EDTA(4-)-like ligand containing an extra phosphinate group. [Co-II(XT)](3-), [Co-III(XT)](2-), and a series of [Ln(XT)](2-) complexes have been prepared. The phosphinate group is not coordinated in the Co complexes but is bound in the lanthanide complexes. Solid state and solution behaviors of Ln-XT species are consistent: both monoprotonated and nonprotonated species have been found. Protonation of the metal complex does not lead to dissociation of a carboxylate; rather, the proton distributes around the molecular ion. The pM values of Ln-XT are comparable to those of Ln-EDTA but are higher than those of Ln-TMDTA. The inclusion of a phosphinate eases the selectivity of an EDTA-type ligand for late lanthanides.}, keywords = {ACID, AGENTS, AMINE PHENOL LIGANDS, ANTIBODY, COMPLEXES, CRYSTAL-STRUCTURES, DERIVATIVES, IONS}, isbn = {0020-1669}, url = {://000169861800011}, author = {Xu, L. and Rettig, S. J. and Orvig, Chris} } @article {5077, title = {Macrocyclic complexes of niobium(III): Synthesis, structure, and magnetic behavior of mononuclear and dinuclear species that incorporate the [P2N2] system}, journal = {Organometallics}, volume = {20}, number = {17}, year = {2001}, note = {ISI Document Delivery No.: 464CMTimes Cited: 12Cited Reference Count: 72}, month = {Aug}, pages = {3752-3761}, type = {Article}, abstract = {{The coordination chemistry of the two mixed donor macrocyclic ligands (R)[P2N2] (where (R)[P2N2] = RP(CH2SiMe2NSiMe2CH2)(2)PR}, keywords = {= PHP(CH2SIME2NSIME2CH2)(2)PPH, AMIDE, ARENE HYDROGENATION, BOND, C-H, CRYSTAL-STRUCTURES, DERIVATIVES, MOLECULAR-STRUCTURE, N BOND-CLEAVAGE, TRIPLE, X-ray structures}, isbn = {0276-7333}, url = {://000170515600024}, author = {Fryzuk,Michael D. and Kozak, C. M. and Bowdridge, M. R. and Jin, W. C. and Tung, D. and Patrick, B. O. and Rettig, S. J.} } @article {5201, title = {Proton- and lanthanide-coordinating properties of the tetraaza macrocycle (EDDA-KA)(2) in aqueous solution}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {79}, number = {5-6}, year = {2001}, note = {ISI Document Delivery No.: 456EVTimes Cited: 4Cited Reference Count: 36}, month = {May}, pages = {1058-1067}, type = {Article}, abstract = {{The new potentially multidentate ligand (EDDA-KA)(2) has been prepared and its acid-base properties determined. Its coordination properties with three lanthanide ions (La3+, Gd3+, and Lu3+) and Fe3+ have been studied in aqueous solution (I = 0.16 M NaCl, 25degreesC) by potentiometric pH, spectrophotometric, and H-1 NMR titrations. In total, eight pK(a) values could be determined by these diverse methods. From the H-1 NMR titrations, all the deprotonation steps could be determined and assigned (in groups). Strong hydrogen bonding among two nitrogen atoms and one oxygen atom on the pyrone ring was observed, and the corresponding pK(a) values were estimated to be 13.2 and 14.0. By comparison with similar systems, an equilibrium constant for the formation of the hydrogen bond was estimated}, keywords = {ACID-BASE, acidity constants, ALKALINE-EARTH, amino, BINDING-PROPERTIES, carboxylate chelator, CHEMISTRY, CONTRAST AGENTS, DERIVATIVES, DYNAMICS, Fe3+, GADOLINIUM, Gd3+, La3+, Lu3+, METAL-COMPLEXES, STABILITIES, stability constants}, isbn = {0008-4042}, url = {://000170070900078}, author = {Song, B. and Kurokawa, G. S. and Liu, S. and Orvig, Chris} } @article {5043, title = {A remarkable temperature-dependent, accidental degeneracy of P-31 NMR chemical shifts in Ru(II) diphosphine/diimine complexes}, journal = {Chemical Communications}, number = {17}, year = {2001}, note = {ISI Document Delivery No.: 469DQTimes Cited: 10Cited Reference Count: 26}, month = {Sep}, pages = {1570-1571}, type = {Article}, abstract = {Several cis-RUX2((R)-BINAP)(diimine) complexes have been prepared, and many of these exhibit an unusual temperature-dependent, accidental degeneracy of the P-31 shifts in their solution NMR spectra.}, keywords = {ASYMMETRIC HYDROGENATION, BINAP, CATALYSIS, CHEMISTRY, DERIVATIVES, KETONES, LIGANDS, PHOSPHINE COMPLEXES, REACTIVITY, RUTHENIUM(II) COMPLEXES}, isbn = {1359-7345}, url = {://000170798800019}, author = {Cyr, P. W. and Patrick, B. O. and James, Brian R.} } @article {5072, title = {Synthesis and structure of the hafnium alkylidene complex [P2Cp]Hf=CHPh(Cl) ([P2Cp] = (eta(5)-C5H3-1,3-(SiMe2CH2PPr2i)(2)))}, journal = {Organometallics}, volume = {20}, number = {8}, year = {2001}, note = {ISI Document Delivery No.: 427FWTimes Cited: 14Cited Reference Count: 16}, month = {Apr}, pages = {1608-1613}, type = {Article}, abstract = {The synthesis, structural characterization, and solution behavior of hafnium complexes stabilized by the potentially tridentate ancillary ligand [P2Cp] ([P2Cp] = (eta (5)-C5H3-1,3-(SiMe2CH2PPr2i)(2))) are described. The reaction of [P2Cp]Li with HfCl4(THT)(2) produces the hafnium trichloride complex [P2Cp]HfCl3 (1), the structure of which was determined by X-ray crystallography. Trichloride 1 is isostructural with the analogous zirconium complex [P2Cp]ZrCl3 (2) in the solid state, but in solution 1 exists as an equilibrium mixture of two isomers that interconvert by fluxional phosphine coordination. Treatment of 1 with 2 equiv of KCH2Ph, followed by thermolysis, yields the first structurally characterized hafnium alkylidene complex, [P2Cp]Hf=CHPh(Cl) (3). A crystal structure determination obtained for 3 shows this complex to be isostructural with the zirconium analogue [P2Cp]Zr=CHR(Cl) (4). The primary difference between the Hf systems presented here and the previously studied Zr analogues is that metal-ligand bonding is stronger in the former, which accounts for shorter bond distances, a greater degree of chemically inertness, and the divergent solution behaviors observed for the trichloride derivatives 1 and 2.}, keywords = {BENZYL, CRYSTAL-STRUCTURE, DERIVATIVES, MOLECULAR-STRUCTURE, PH, SIME3, trichloride, ZIRCONIUM}, isbn = {0276-7333}, url = {://000168395000016}, author = {Fryzuk,Michael D. and Duval, P. B. and Patrick, B. O. and Rettig, S. J.} } @article {4946, title = {Accurate density-functional calculation of core-electron binding energies of some substituted benzenes}, journal = {Bulletin of the Chemical Society of Japan}, volume = {73}, number = {11}, year = {2000}, note = {ISI Document Delivery No.: 380KRTimes Cited: 7Cited Reference Count: 32}, month = {Nov}, pages = {2453-2460}, type = {Article}, abstract = {The core electron binding energies (CEBE{\textquoteright}s) of benzene, seven monosubstituted benzenes (Ph-X) and one disubstituted benzene (p-NH2-C6H4-NO2) were calculated using density-functional theory (DFT). The unrestricted generalized transition-state (uGTS) model was employed. The DeMon DFT program with a combined functional of Becke{\textquoteright}s exchange (B88) with Perdew{\textquoteright}s correlation (P86) was used. The average absolute deviation of the calculated CEBE{\textquoteright}s of the title compounds was 0.3 eV when the cc-pVDZ basis set was used. The "CEBE shift" of the ring carbon in Ph-X was calculated while taking the CEBE on the ring carbon in Ph-H as a reference. The thus-calculated CEBE shifts agree with experiment within the value of the average absolute deviation, 0.1 eV. The signs and quantitative numerical values of the CEBE shifts are very close to the corresponding Hammett sigma constants.}, keywords = {APPROXIMATION, BORON, DERIVATIVES, GAS, PARAMETERS, RAY PHOTOELECTRON-SPECTROSCOPY, SPECTRA, ZETA BASIS-SET}, isbn = {0009-2673}, url = {://000165701500004}, author = {Takahata, Y. and Chong, D. P.} } @article {4903, title = {Improved synthesis of isogranulatimide, a G2 checkpoint inhibitor. Syntheses of didemnimide C, isodidemnimide A, neodidemnimide A, 17-methylgranulatimide, and isogranulatimides A-C}, journal = {Journal of Organic Chemistry}, volume = {65}, number = {2}, year = {2000}, note = {ISI Document Delivery No.: 276YFTimes Cited: 44Cited Reference Count: 35}, month = {Jan}, pages = {530-535}, type = {Article}, abstract = {A concise, improved synthesis of isogranulatimide (6), a naturally occurring substance with G2 checkpoint inhibition activity, is described. Also reported are the syntheses of didemnimide C (18), isodidemnimide A (24), neodidemnimide A (36), 17-methylgranulatimide (9), and isogranulatimides A (10), B (11), and C (12). Compounds 9-12, congeners of isogranulatimide (6), are now available for biological evaluation.}, keywords = {BHK CELLS, CAFFEINE, CANCER, CELL-CYCLE CHECKPOINTS, CISPLATIN, DERIVATIVES, DNA-REPLICATION, ENHANCEMENT, IMIDAZOLES, RADIOSENSITIZATION}, isbn = {0022-3263}, url = {://000084905400039}, author = {Piers, E. and Britton, R. and Andersen, R. J.} } @article {4850, title = {Structural studies of organoboron compounds, Part 72 - Nitrones and oximes of bifunctional carbonyl compounds and their reaction products with diarylborinic acids. Crystal and molecular structure of examples of five-, six-, and seven-membered boron chelat}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {78}, number = {10}, year = {2000}, note = {ISI Document Delivery No.: 366QGTimes Cited: 9Cited Reference Count: 74}, month = {Oct}, pages = {1325-1344}, type = {Article}, abstract = {{Synthesis has been carried out of diarylboron chelates of 2- and 3-hydroxynitrones, of 2- and 3-hydroxyoximes, and of 2-carboxynitrones and a 2-carboxyoxime. The structures have been determined from spectroscopic data and from X-ray analyses of 5d, 9a, 11b, and 19. Crystals (at 180 K) of 5d are monoclinic}, keywords = {carboxynitrones, carboxyoximes, CHEMISTRY, COBALT(III), crystal structure, DERIVATIVES, diarylboron chelates, DIPHENYLBORINIC ACID, hydroxynitrones, HYDROXYOXIME STRUCTURE, hydroxyoximes, LIGAND, METAL-COMPLEXES, N-(2-HYDROXYALKYL)NITRONES, ORGANOBORON COMPOUNDS, RING-CHAIN ISOMERISM}, isbn = {0008-4042}, url = {://000090015600009}, author = {Kliegel, W. and Lubkowitz, G. and Pokriefke, J. O. and Rettig, S. J. and Trotter, J.} } @article {4807, title = {Synthesis, characterization, and reactivity of scandium chloro, alkyl, aryl, and borohydride complexes, Sc(eta(5)-C5H5)R[N(SiMe2CH2P(i)Pr-2)(2)] (R = Cl, Me, Ph, and BH4)}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {78}, number = {7}, year = {2000}, note = {ISI Document Delivery No.: 343HDTimes Cited: 16Cited Reference Count: 44}, month = {Jul}, pages = {1003-1012}, type = {Article}, abstract = {{Reaction of ScCl2(THF)[N((SiMe2CH2PPr2)-Pr-i)(2)] with NaCp(DME) leads to Sc(eta(5)-C5H5)Cl[N((SiMe2CH2PPr2)-Pr-i)(2)] (1). The X-ray crystal structure shows the scandium centre to reside in a square pyramidal environment with the [N((SiMe2CH2PPr2)-Pr-i)(2)] - ligand bound in a pseudo-meridional fashion. The H-1 NMR spectrum is consistent with a C-s symmetric structure in solution. Metathesis of the chloride ligand with RLi (R = Me, Ph, BH4) yields the five-coordinate species Sc(eta(5)-C5H5)R[N((SiMe2CH2PPr2)-Pr-i)(2)]. Phenyl 3 and borohydride 4 are isolated as crystalline solids, while methyl 2 resisted crystallization. 2-4 exhibit H-1 NMR spectra consistent with C-s symmetric solution structures. Sc(eta(5)-C5H5)Ph[N((SiMe2CH2PPr2)-Pr-i)(2)] (3) was characterized in the solid state and found to have a similar geometry to that of the parent chloride. Reaction of Sc(eta(5)-C5H5)Me[N((SiMe2CH2PPr2)-Pr-i)(2)] (2) with NH2R (R = Ph, Bu-t) yields the amides Sc(eta(5)-C5H5)NHPh[N((SiMe2CH2PPr2)-Pr-i)(2)] (5) and Sc(eta(5)-C5H5)(NHBu)-Bu-t- [N((SiMe2CH2PPr2)-Pr-i)(2)] (6) via sigma-bond metathesis routes; these reactions are accompanied by a competing reaction at the scandium-amide bond to produce the protonated ligand, HN((SiMe2CH2PPr2)-Pr-i)(2) 5 and 6 are also produced by salt-elimination from the chloride 1 and LiNHR (R = Ph, Bu-t). Sc(eta(5)-C5H5)(BH4)[N((SiMe2CH2PPr2)-Pr-i)(2)] (4) reacts with PMe3 to produce the putative hydride, Sc(eta(5)-C5H5)H[N((SiMe2CH2PPr2)-Pr-i)(2)] (7); this species was identified in solution. An equilibrium between 4, PMe3, 7, and PMe3,BH3 exists which greatly favors the starting scandium-borohydride. Crystals of Sc(eta(5)-C5H5)Cl[N((SiMe2CH2PPr2)-Pr-i)(2)] (1) are monoclinic}, keywords = {ALKANE ELIMINATION, BETA-HYDROGEN, borohydride, CHAIN, CHEMISTRY, DERIVATIVES, hydride, LANTHANIDE, PERMETHYLSCANDOCENE, PROPAGATION, RAY CRYSTAL-STRUCTURE, SCANDIUM, sigma-bond metathesis, TETRAHYDROBORATE COMPLEXES, ZIEGLER-NATTA POLYMERIZATION}, isbn = {0008-4042}, url = {://000088695300009}, author = {Fryzuk,Michael D. and Giesbrecht, G. R. and Rettig, S. J.} } @article {4955, title = {X-ray crystallographic and C-13 NMR investigations of the effects of electron-withdrawing groups on a series of pyrroles}, journal = {Organic Letters}, volume = {2}, number = {23}, year = {2000}, note = {ISI Document Delivery No.: 373RBTimes Cited: 9Cited Reference Count: 25}, month = {Nov}, pages = {3587-3590}, type = {Article}, abstract = {[GRAPHICS] A series of pyrroles substituted with various electron-withdrawing groups (EWGs) on the N atom have been synthesized and full characterization including X-ray crystal structures obtained, Analysis of C-13 chemical shifts and X-ray crystal structures reveals that a trend between decreased aromaticity and the strength of the EWG exists. Experimental results regarding alternative mechanisms of nucleophilic substitution reactions can thus be rationalized.}, keywords = {DERIVATIVES, NUCLEAR MAGNETIC-RESONANCE, THIOPHENES}, isbn = {1523-7060}, url = {://000165301700015}, author = {Thompson, A. and Gao, S. and Modzelewska, G. and Hughes, D. S. and Patrick, B. and Dolphin, D.} } @article {4704, title = {{Formation of Pd2X2(mu-S)(mu-dpm)(2) by reaction of PdX2(dpm) with H2S in the presence of alumina (X = halogen}, journal = {Journal of Molecular Catalysis a-Chemical}, volume = {139}, number = {2-3}, year = {1999}, note = {ISI Document Delivery No.: 162RZTimes Cited: 5Cited Reference Count: 21}, month = {Mar}, pages = {159-169}, type = {Article}, abstract = {Alumina promotes the reaction of PdX2(dpm) (3) (X = Cl, Br, I) with H2S to form Pd2X2(mu-S)(dpm)(2) (2)(1) and HX, with chemisorption of the HX (quantified by titration) providing the driving force; although no intermediate species are detected, the reaction likely proceeds via mercapto species formed via {\textquoteright}alumina activated H2S{\textquoteright}. XPS studies show interactions of species 2 and 3 with alumina, these interactions being weak as demonstrated by recovery of the species on dissolution using an appropriate solvent. For the iodide system, adsorbed HI on alumina undergoes partial photodecomposition to give I-2 and H atoms. (C) 1999 Elsevier Science B.V. All rights reserved.}, keywords = {ALUMINA, ASPECTS, bis(diphenylphosphino)methane, CONVERSION, CRYSTAL, DERIVATIVES, DINUCLEAR PALLADIUM(I) COMPLEXES, H2S, HYDROGEN-SULFIDE, Mechanistic, models, Pd2X2(mu-S)(mu-dpm)(2), PdX2(dpm), SURFACE}, isbn = {1381-1169}, url = {://000078361700006}, author = {Wong, T. Y. H. and James, Brian R. and Wong, P. C. and Mitchell, K. A. R.} } @article {4610, title = {The metabolites of dietary chlorophylls}, journal = {Phytochemistry}, volume = {50}, number = {2}, year = {1999}, note = {ISI Document Delivery No.: 160EBTimes Cited: 15Cited Reference Count: 70}, month = {Jan}, pages = {195-202}, type = {Review}, abstract = {Chlorophylls, the green pigments responsible for photosynthesis in plants, algae and bacteria, are also part of the daily diet of herbivorous feeders. Numerous metabolic derivatives of the major green pigment, chlorophyll-a, have been found in a wide variety of organisms during the last decade. Studies of these metabolites show that some are antioxidants or cellular signaling mediators in vivo. The metabolites of bacteriochlorophylls-c and d, recently found in the deep-sea dragon fish, Malacosteus niger, function as a visual photosensitizer, enabling the fish to seek their prey in {\textquoteright}the dark{\textquoteright}. Discovery of these metabolites as well as their interesting biological functions raises questions as to the roles of chlorophyll derivatives in the chemical ecology of herbivorous life forms. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.}, keywords = {antioxidant, AUTOXIDATION, cell signaling, CHLORIN, CHLOROPHYLL, DERIVATIVES, DIET, ESTERS, MARINE ORGANISMS, METABOLISM, PHOTOSENSITIZER, PI-CATION RADICALS, porphyrins, PRODUCTS, RUDITAPES-PHILIPPINARUM, TUNICHLORIN}, isbn = {0031-9422}, url = {://000078216500001}, author = {Ma, L. F. and Dolphin, D.} } @article {4493, title = {A novel stepwise degradation of porphyrins. Synthesis and structural characterization of meso-tetraphenylchlorophinato nickel(II) and meso-tetraphenylsecochlorinato nickel(II)}, journal = {Journal of the American Chemical Society}, volume = {121}, number = {11}, year = {1999}, note = {ISI Document Delivery No.: 180AUTimes Cited: 27Cited Reference Count: 33}, month = {Mar}, pages = {2609-2610}, type = {Article}, keywords = {CARBAPORPHYRINS, CLEAVAGE, DERIVATIVES, FLEXIBILITY, HYDROPORPHYRINS, macrocycle, SYSTEM}, isbn = {0002-7863}, url = {://000079363300039}, author = {Bruckner, C. and Sternberg, E. D. and Macalpine, J. K. and Rettig, S. J. and Dolphin, D.} } @article {4457, title = {Organometallic oxides: Preparation and properties of the clusters [(eta-C5Me5)V(mu(3)-O)](4) and [(eta-C5Me5)V](4)(mu-O)(6) by reductive aggregation of (eta-C5Me5)VCl2(O)}, journal = {Organometallics}, volume = {18}, number = {5}, year = {1999}, note = {ISI Document Delivery No.: 174EYTimes Cited: 10Cited Reference Count: 56}, month = {Mar}, pages = {870-879}, type = {Article}, abstract = {Reduction of Cp*VCl2(O) (Cp* = eta-C5Me5) by the powerful reductants sodium, potassium, magnesium, or calcium or the amalgams of these metals gave a mixture of the black cubane-like cluster [Cp*V(mu(3)-O)](4) and the black-green adamantane-like cluster [Cp*V](4)(mu-O)(6). A concurrent coproduct of the formation of [Cp*V](4)(mu-O)(6) was dark purple [Cp*V(mu-Cl)(2)](3). The formation of [Cp*V]4(mu-O)(6) was favored in toluene, whereas [Cp*V(mu(3)-O)](4) was favored in tetrahydrofuran. The identity of the reductant did not influence the ratio of [Cp*V]4(mu-O)(6) to [Cp*V(mu(3)-O)](4) produced. A scheme for the reduction is proposed; the key intermediate is [Cp*VClO](2). The cluster [Cp*V(mu(3)-O)](4) was paramagnetic (mu(eff) = 2.35 mu(B) at 300 K), and [Cp*V]4(mu-O)(6) was diamagnetic. The syntheses of [Cp*VCl(O)](2)(mu-O) by treatment of Cp*VCl2(O) with Ag2CO3 and [Cp*VCl(mu-O)](4) (which is paramagnetic, mu(eff) = 4.51 mu(B) at 300 K) by reduction of Cp*VCl2(O) with mercury are reported.}, keywords = {CRYSTAL-STRUCTURES, CUBANE, D-BLOCK, DERIVATIVES, ELECTRONIC-STRUCTURES, MAGNETIC-PROPERTIES, {COMPLEXES}, isbn = {0276-7333}, url = {://000079022200011}, author = {Abernethy, C. D. and Bottomley, F. and Day, R. W. and Decken, A. and Summers, D. A. and Thompson, R. C.} } @article {4545, title = {Preparation and reactivity of zirconium(III), niobium(III), and molybdenum(III) complexes stabilized by a cyclopentadienyl unit with pendant phosphine donors}, journal = {Organometallics}, volume = {18}, number = {20}, year = {1999}, note = {ISI Document Delivery No.: 244CDTimes Cited: 14Cited Reference Count: 55}, month = {Sep}, pages = {4050-4058}, type = {Article}, abstract = {This paper deals with the organometallic chemistry of the trivalent second-row transition metals of groups 4-6, namely, Zr, Nb, and Mo, with the cyclopentadienyldiphosphine ligand [eta(5)-C5H3-1,3-(SiMe2CH2PR2)(2)], abbreviated as [(P2Cp)-P-R] (where R = i-Pr and Ph). The Zr(IV) complex [i-PrP2Cp]ZrCl3 undergoes reduction with Na/Hg to form the trivalent Zr derivative, [i-PrP2Cp]ZrCl2, which undergoes a metathetical reaction with MeMgBr to yield the monomethyl derivative [i-PrP2Cp]Zr(CH3)Cl. The reaction of the Zr(III) complex [i-PrP2Cp]ZrCl2 with excess carbon monoxide results in disproportionation to the Zr(IV) complex, [i-PrP2Cp]ZrCl3, and the Zr(II) compound [i-PrP2Cp]Zr(CO)(2)Cl. This reaction is reversible, and upon removal of CO the starting material, [i-PrP2Cp]ZrCl2 is formed. The preparation of the diamagnetic Nb(III) complex [(P2Cp)-P-R]NbCl2 is achieved by the reaction of NbCl3(DME) with [(P2Cp)-P-R]Li. [(P2Cp)-P-R]NbCl2 complexes react with excess CO to form the CO adducts whose solid-state structures have been determined. The Nb(IV) derivatives [(P2Cp)-P-R]NbCl3 are formed via the reaction of [(P2Cp)-P-R]NbCl2 with PbCl2. These complexes can also be produced when Nb(O)Cl-3(THF)(2) is allowed to react with excess [(P2Cp)-P-R]Li. These Nb(IV) derivatives are ESR active, and their solid-state molecular structures show distorted octahedral geometries around the Nb center. MoCl3(THF)(3) reacts with [(P2Cp)-P-R]Li to generate the corresponding Mo(III) complexes [(P2Cp)-P-R]MoCl2. These compounds are low-spin, paramagnetic complexes as evidenced by their ESR spectra.}, keywords = {CARBONYL, CHEMISTRY, CONVENIENT, DERIVATIVES, HALOGENO, LINKAGE, {BONDS}, isbn = {0276-7333}, url = {://000083033500018}, author = {Fryzuk,Michael D. and Jafarpour, L. and Rettig, S. J.} } @article {4546, title = {Synthesis and structure of the tantalum trimethyl complex [P2N2]TaMe3 and its conversion to the tantalum methylidene species [P2N2]Ta = CH2(Me) ([P2N2] = PhP(CH2SiMe2NSiMe2CH2)(2)PPh)}, journal = {Organometallics}, volume = {18}, number = {20}, year = {1999}, note = {ISI Document Delivery No.: 244CDTimes Cited: 25Cited Reference Count: 42}, month = {Sep}, pages = {4059-4067}, type = {Article}, abstract = {A tantalum(V) trimethyl complex and its photolysis product, a relatively stable tantalum(V) methyl methylidene, were prepared using the macrocyclic bis(amido-phosphine) PhP(CH2SiMe2NSiMe2CH2)(2)PPh, abbreviated [P2N2], as an ancillary ligand. The methylidene precursor [P2N2]TaMe3 is generated by the reaction of [P2N2]Li-2. C4H8O2 (C4H8O2 = 1,4-dioxane) with TaMe3Cl2. The solid-state X-ray molecular structure demonstrates that the geometry of [P2N2]TaMe3 is a seven-coordinate capped trigonal prism, and NMR studies confirm this is also true in solution at low temperature. Photolysis with a UV source generates [P2N2]Ta=CH2(Me), with the elimination of methane. The X-ray solid-state molecular structure of [P2N2]Ta=CH2(Me) is intermediate between octahedral and trigonal-prismatic geometry. Variable-temperature NMR studies demonstrate that the double-bonded methylidene moiety rotates with a barrier of 33.5 +/- 0.6 kJ/mol, in contrast to the larger barrier estimated for the previously characterized 18-electron complex (eta(5)-C5H5)(2)Ta=CH2(Me). Reaction of [P2N2]TaMe3 with Ph3C+BF4- or PhNMe2H+B(C6F5)(4)(-) produced {[P2N2]TaMe2}+BF4- and {[P2N2]TaMe2}B+(C6F5)(4)(-), respectively. Attempts to deprotonate {[P2N2]TaMe2}(+) did not provide a chemical route to [P2N2]Ta=CH2(Me) and instead generated either [P2N2]TaMe2F or the product of deprotonation of the [P2N2] ligand methylene backbone, Ta(Me-2)[(CHSiMe2NSiMe2CH2P(Ph)CH2SiMe2NSiMe2CH2PPh)], depending on the base and counteranion used.}, keywords = {ABSTRACTION, CATALYSIS, COORDINATION, CRYSTAL-STRUCTURES, DECOMPOSITION, DERIVATIVES, imido, METAL-CARBON BONDS, METHYLENE COMPLEX, REACTIVITY}, isbn = {0276-7333}, url = {://000083033500019}, author = {Fryzuk,Michael D. and Johnson, S. A. and Rettig, S. J.} } @article {4280, title = {Chelate ring-opening ruthenium complexes: X-ray crystal structure and solution studies of cis,trans-bis(2-dimethyl-aminoethyl)diphenylphosphino(dichloro)ruthenium (II)}, journal = {Inorganica Chimica Acta}, volume = {273}, number = {1-2}, year = {1998}, note = {ISI Document Delivery No.: ZP204Times Cited: 13Cited Reference Count: 34XXXIII International Conference on Coordination ChemistryAUG 30-SEP 04, 1998FLORENCE, ITALY}, month = {May}, pages = {1-7}, type = {Proceedings Paper}, abstract = {{The Ru(II) complex cis,trans-[Ru(Me(2)NCH(2)Ch(2)PPh(2)-P,N)(2)Cl-2] (1) has been characterized in the solid state and in solution. X-ray crystallography showed that complex 1 is monoclinic, space group C-2/c; a = 36.0421}, keywords = {aminophosphine complexes, chelate ring complexes, crystal structures, DERIVATIVES, IMIDAZOLE, METAL-COMPLEXES, PHOSPHINE-LIGANDS, ruthenium complexes, SERIES}, isbn = {0020-1693}, url = {://000073728200002}, author = {Guo, Z. J. and Habtemariam, A. and Sadler, P. J. and James, Brian R.} } @article {4263, title = {One-electron transformations of paramagnetic cobalt complexes. Synthesis and structure of cobalt(II) amidodiphosphine halide and alkyl complexes and their reaction with alkyl halides}, journal = {Journal of the American Chemical Society}, volume = {120}, number = {39}, year = {1998}, note = {ISI Document Delivery No.: 127ZPTimes Cited: 33Cited Reference Count: 106}, month = {Oct}, pages = {10126-10135}, type = {Review}, abstract = {Complexes of the type CoX[N(SiMe2CH2PPh2)(2)], where X = Cl, Br, or I, can be prepared via reaction of CoX2 with LiN(SiMe2CH2PPh2)(2); these derivatives are tetrahedral high-spin d(7) systems. Reaction of these halide complexes with organolithium, sodium, or potassium reagents generates square-planar, low-spin hydrocarbyl complexes of the formula CoR[N(SiMe2CH2PPh2)(2)] (R = Me, CH2Ph, CH2SiMe3, C5H5). One-electron oxidations have been carried out; only the product of halide abstraction is observed. For example, addition of PhCH2X to the halide derivatives CoX[N(SiMe2CH2PPh2)(2)] generates trivalent, paramagnetic complexes, CoX2[N(SiMe2CH2PPh2)(2)]; these derivatives show variable-temperature magnetic susceptibility data that are consistent with zero-field splitting of the S = 1 state. Addition of methyl bromide or methyl iodide to low-spin CoMe[N(SiMe2CH2PPh2)(2)] results in the formation of the Co(II) halide derivatives CoX[N(SiMe2CH2PPh2)(2)] along with methane and bibenzyl. It is proposed that the Co(III) methyl halide complex CoMe(X) [N(SiMe2CH2PPh2)(2)] is unstable and loses methyl radical homolytically to generate the Co(II) halide derivative; the methyl subsequently reacts with the toluene solvent to produce methane and bibenzyl. Addition of excess benzyl halides has also been found to generate the Co(II) halide complexes initially, followed by a one-electron oxidation to the Co(II) dihalide derivatives. In much of the one-electron chemistry of the Co(II) derivatives incorporating the amidodiphosphine ligand, the decomposition of the putative but unstable Cs(III) alkyl halide derivative CoRX[N(SiMe2CH2PPh2)(2)] is proposed as a recurring event.}, keywords = {17-ELECTRON, BOND-DISSOCIATION ENERGIES, COORDINATION CHEMISTRY, D6 ML5 COMPLEXES, DERIVATIVES, HIGHER OXIDATION-STATES, KINETICS, LIGAND, ORGANIC HALIDES, RADICAL REACTIONS}, isbn = {0002-7863}, url = {://000076381000017}, author = {Fryzuk,Michael D. and Leznoff, D. B. and Thompson, R. C. and Rettig, S. J.} } @article {4200, title = {Second-harmonic generation studies of chiral organic salts}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {76}, number = {11}, year = {1998}, note = {ISI Document Delivery No.: 205KKTimes Cited: 6Cited Reference Count: 39}, month = {Nov}, pages = {1616-1632}, type = {Article}, abstract = {Second-harmonic generation in the solid state is restricted to materials that crystallize in non-centrosymmetric space groups. Unfortunately, the vast majority of solids crystallize in centrosymmetric space groups and are therefore SHG-inactive. The requirement for solid-state asymmetry is addressed in a new series of organic salts. The acid p-nitrophenylglycine, SHG-inactive due to its centrosymmetric (P1) packing, was coupled to six optically pure amines to form salts and (or) complexes that, by virtue of their chiral counterion, crystallized in non-centrosymmetric space groups. The 1064 nm output from a Nd:YAG laser produced 532 nm second-harmonic generation from each of the six salts, with, three of the salts producing second-harmonic intensities at least an order of magnitude greater than that of our standard, urea. X-ray crystallographic analysis was carried out on five of the six salts, and an attempt was made to rationalize the second-harmonic intensity of each of these five salts based on the orientation of its molecular charge-transfer axis in the unit cell and on its chromophore density.}, keywords = {asymmetric, chiral organic salts, crystal structures, DERIVATIVES, INDUCTION, MOLECULAR-CRYSTALS, NONLINEAR OPTICS, NONLINEAR-OPTICAL-MATERIALS, second-harmonic generation, SOLID-STATE PHOTOCHEMISTRY}, isbn = {0008-4042}, url = {://000080819700019}, author = {Borecka-Bednarz, B. and Bree, A. V. and Patrick, B. O. and Scheffer, J. R. and Trotter, J.} } @article {4200, title = {Second-harmonic generation studies of chiral organic salts}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {76}, number = {11}, year = {1998}, note = {ISI Document Delivery No.: 205KKTimes Cited: 6Cited Reference Count: 39}, month = {Nov}, pages = {1616-1632}, type = {Article}, abstract = {Second-harmonic generation in the solid state is restricted to materials that crystallize in non-centrosymmetric space groups. Unfortunately, the vast majority of solids crystallize in centrosymmetric space groups and are therefore SHG-inactive. The requirement for solid-state asymmetry is addressed in a new series of organic salts. The acid p-nitrophenylglycine, SHG-inactive due to its centrosymmetric (P1) packing, was coupled to six optically pure amines to form salts and (or) complexes that, by virtue of their chiral counterion, crystallized in non-centrosymmetric space groups. The 1064 nm output from a Nd:YAG laser produced 532 nm second-harmonic generation from each of the six salts, with, three of the salts producing second-harmonic intensities at least an order of magnitude greater than that of our standard, urea. X-ray crystallographic analysis was carried out on five of the six salts, and an attempt was made to rationalize the second-harmonic intensity of each of these five salts based on the orientation of its molecular charge-transfer axis in the unit cell and on its chromophore density.}, keywords = {asymmetric, chiral organic salts, crystal structures, DERIVATIVES, INDUCTION, MOLECULAR-CRYSTALS, NONLINEAR OPTICS, NONLINEAR-OPTICAL-MATERIALS, second-harmonic generation, SOLID-STATE PHOTOCHEMISTRY}, isbn = {0008-4042}, url = {://000080819700019}, author = {Borecka-Bednarz, B. and Bree, A. V. and Patrick, B. O. and Scheffer, J. R. and Trotter, J.} } @article {4165, title = {Crystal engineering for absolute asymmetric synthesis through the use of meta-substituted aryl groups}, journal = {Tetrahedron Letters}, volume = {38}, number = {18}, year = {1997}, note = {ISI Document Delivery No.: WW958Times Cited: 14Cited Reference Count: 17}, month = {May}, pages = {3135-3138}, type = {Article}, abstract = {A significant tendency towards crystallization in chiral space groups has been found for 4-benzyloxy-2-pyridones whose phenyl groups are meta-substituted (m-Cl, m-Br, m-Me and m-OMe). Irradiation of single crystals of three of these materials leads to optically active beta-lactam derivatives in high chemical and optical yields via an allowed disrotatory electrocyclization. (C) 1997 Elsevier Science Ltd.}, keywords = {DERIVATIVES, PHOTOCHEMISTRY, PHOTOREARRANGEMENT}, isbn = {0040-4039}, url = {://A1997WW95800004}, author = {Wu, L. C. and Cheer, C. J. and Olovsson, G. and Scheffer, J. R. and Trotter, J. and Wang, S. L. and Liao, F. L.} } @article {4165, title = {Crystal engineering for absolute asymmetric synthesis through the use of meta-substituted aryl groups}, journal = {Tetrahedron Letters}, volume = {38}, number = {18}, year = {1997}, note = {ISI Document Delivery No.: WW958Times Cited: 14Cited Reference Count: 17}, month = {May}, pages = {3135-3138}, type = {Article}, abstract = {A significant tendency towards crystallization in chiral space groups has been found for 4-benzyloxy-2-pyridones whose phenyl groups are meta-substituted (m-Cl, m-Br, m-Me and m-OMe). Irradiation of single crystals of three of these materials leads to optically active beta-lactam derivatives in high chemical and optical yields via an allowed disrotatory electrocyclization. (C) 1997 Elsevier Science Ltd.}, keywords = {DERIVATIVES, PHOTOCHEMISTRY, PHOTOREARRANGEMENT}, isbn = {0040-4039}, url = {://A1997WW95800004}, author = {Wu, L. C. and Cheer, C. J. and Olovsson, G. and Scheffer, J. R. and Trotter, J. and Wang, S. L. and Liao, F. L.} } @article {3870, title = {Organometallic halides: Preparation and physical and chemical properties of tris[(eta-pentamethylcyclopentadienyl)dichlorovanadium], [(eta-C5Me5)V(mu-Cl)(2)](3)}, journal = {Organometallics}, volume = {16}, number = {9}, year = {1997}, note = {ISI Document Delivery No.: WX030Times Cited: 14Cited Reference Count: 60}, month = {Apr}, pages = {1865-1869}, type = {Article}, abstract = {The cluster [(eta-C5Me5)V(mu-Cl)(2)](3) was synthesized from VCl3(thf)(3) and (Bu3SnC5Me5)-Sn-n. It was oxidized by O-2 to give (eta-C5Me5)VCl2(O), and by NaN3 to give [(eta-C5Me5)VCl(mu-N)](2). X-ray diffraction showed that [(eta-C5Me5)V(mu-Cl)(2)](3) had an equilateral triangle of vanadium atoms (mean V-V 3.367 (2) Angstrom), with each edge of the triangle symmetrically bridged by two chlorine atoms. The cluster contains six core electrons. The cluster [(eta-C5Me5)V(mu-Cl-2](3) had a magnetic moment of 2.92 mu(B) at room temperature and showed antiferromagnetic behavior.}, keywords = {CHROMIUM(III), CRYSTAL-STRUCTURE, DERIVATIVES, HALF-SANDWICH COMPLEXES, MAIN-GROUP ELEMENTS, multiple bonds, OXIDES, OXO, TRANSITION-METALS, {ALKYLS}, isbn = {0276-7333}, url = {://A1997WX03000011}, author = {Abernethy, C. D. and Bottomley, F. and Decken, A. and Thompson, R. C.} } @article {4143, title = {Thermal alkane C-H bond activation by a tungsten alkylidene complex: The reversal of alpha-hydrogen elimination}, journal = {Journal of the American Chemical Society}, volume = {119}, number = {21}, year = {1997}, note = {ISI Document Delivery No.: XB674Times Cited: 52Cited Reference Count: 36}, month = {May}, pages = {5071-5072}, type = {Article}, keywords = {ABSTRACTION, ADDUCTS, ARYL, BINDING, CHEMISTRY, DERIVATIVES, LIGANDS, METAL-COMPLEXES, REACTIVITY, tantalum}, isbn = {0002-7863}, url = {://A1997XB67400046}, author = {Tran, E. and Legzdins,Peter} } @article {3756, title = {Characterization of five-coordinate ruthenium(II) phosphine complexes by X-ray diffraction and solid-state P-31 CP/MAS NMR studies and their reactivity with sulfoxides and thioethers}, journal = {Inorganic Chemistry}, volume = {35}, number = {25}, year = {1996}, note = {ISI Document Delivery No.: VW819Times Cited: 27Cited Reference Count: 41}, month = {Dec}, pages = {7304-7310}, type = {Article}, abstract = {{P-31 CP/MAS NMR spectroscopy is examined as a method of characterization for ruthenium(II) phosphine complexes in the solid state, and the results are compared with X-ray crystallographic data determined for RuCl2(dppb)(PPh(3)) (dppb = Ph(2)P(CH2)(4)PPh(2)), RuBr2(PPh(3))(3), and the previously determined RuCl2(PPh(3))(3). Crystals of RuBr2(PPh(3))(3) (C54H45Br2P3Ru) are monoclinic, space group P2(1)/a, with a = 12.482(4) Angstrom}, keywords = {amine, ANGLE SPINNING TECHNIQUES, CATALYSTS, DERIVATIVES, IMINE, LIGANDS, NUCLEAR MAGNETIC-RESONANCE, PLATINUM(II), triphenylphosphine}, isbn = {0020-1669}, url = {://A1996VW81900019}, author = {Macfarlane, K. S. and Joshi, A. M. and Rettig, S. J. and James, Brian R.} } @article {3844, title = {Homoleptic carbonyl cations of palladium(I), palladium(II), platinum(II), and gold(I) - Simplified synthetic routes to their fluoroantimonate(V) salts}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {74}, number = {11}, year = {1996}, note = {ISI Document Delivery No.: WC124Times Cited: 8Cited Reference Count: 68}, month = {Nov}, pages = {1952-1958}, type = {Article}, abstract = {{The original synthetic routes to the new noble metal carbonyl cations [Au(CO)(2)](+) and [M(CO)(4)](2+)}, keywords = {ACIDS, and Pt(II), carbonylations in strong acidic media, COMPLEXES, DERIVATIVES, FLUOROSULFATES, MAS NMR-SPECTRA, metal carbonyl cations of Au(I), MONOXIDE, NOBLE-METALS, Pd(I), Pd(II), reactions in liquid SbF5, reductive carbonylation in liquid SbF5, solvolysis, UNDECAFLUORODIANTIMONATE(V), VIBRATIONAL-SPECTRA}, isbn = {0008-4042}, url = {://A1996WC12400009}, author = {Wang, C. Q. and Siu, S. C. and Hwang, G. and Bach, C. and Bley, B. and Bodenbinder, M. and Willner, H. and Aubke, F.} } @article {3630, title = {A multiple-quantum H-1 NMR study of conformational biasing of biphenyl in a nematic liquid crystal}, journal = {Journal of Magnetic Resonance Series A}, volume = {118}, number = {2}, year = {1996}, note = {ISI Document Delivery No.: TZ082Times Cited: 24Cited Reference Count: 42}, month = {Feb}, pages = {264-271}, type = {Article}, abstract = {Multiple-quantum H-1 NMR spectroscopy was used to simplify the analysis of the complicated one-quantum spectrum of the 10-spin molecule biphenyl dissolved in a nematic solvent. An eight-quantum spectrum was analyzed to obtain estimates of all dipolar coupling constants and chemical shifts, which were used as a starting point to solve the one-quantum spectrum, The dipolar couplings from the one-quantum spectrum were used, in combination with those determined in a previous study using different liquid-crystal solvents, to obtain vibrationally corrected geometrical parameters and orientational order parameters, The effective internal rotational potential was found to be shifted slightly toward a more planar configuration relative to the gas-phase potential, with an equilibrium dihedral angle of 37 degrees. (C) 1996 Academic Press, Inc.}, keywords = {BARRIER, DERIVATIVES, GASEOUS, INTERNAL-ROTATION, MIXTURES, MOLECULAR-STRUCTURE, PERDEUTERATED BIPHENYL, SOLVENTS, SPECTRA, SPECTROSCOPY, STATE}, isbn = {1064-1858}, url = {://A1996TZ08200013}, author = {Chandrakumar, T. and Polson, J. M. and Burnell, E. E.} } @article {3739, title = {Novel synthetic routes to the anionic alkylidene complex [Cp*Mo(NO)(CH(2)SiMe(3))(=CHSiMe(3))](-) from its neutral dialkyl precursor}, journal = {Organometallics}, volume = {15}, number = {19}, year = {1996}, note = {ISI Document Delivery No.: VH293Times Cited: 13Cited Reference Count: 38}, month = {Sep}, pages = {3907-3909}, type = {Article}, abstract = {Conversion of the dialkyl nitrosyl complex Cp*Mo(NO)(CH(2)SiMe(3))(2) (1) to the lithium salt of the anionic alkylidene complex [Cp*Mo(NO)(CH(2)SiMe(3))(=CHSiMe(3))](2)[Li-2(THF)(3)] (2) may be effected with each of the lithium reagents LiN(SiMe(3))(2), LDA, or LiPPh(2). Interestingly, each transformation follows a different mechanistic pathway.}, keywords = {DERIVATIVES, H BOND ACTIVATION, LIGAND, lithium, {DECOMPOSITION}, isbn = {0276-7333}, url = {://A1996VH29300002}, author = {Legzdins,Peter and Sayers, S. F.} } @article {3755, title = {Nucleophilic reaction of 1,8-diazabicyclo[5.4.0]undec-7-ene and 1,5-diazabicyclo-[4.3.0]non-5-ene with methyl pheophorbide a. Unexpected products}, journal = {Tetrahedron}, volume = {52}, number = {3}, year = {1996}, note = {ISI Document Delivery No.: TL974Times Cited: 17Cited Reference Count: 19}, month = {Jan}, pages = {849-860}, type = {Article}, abstract = {Trialkylsilyl triflates promote the direct nucleophilic reaction of {\textquoteright}{\textquoteright}non-nucleophilic DBU and DBN{\textquoteright}{\textquoteright} with methyl pheophorbide a (1) to give substituted chlorin e(6) amides 3 and 4, where the bicyclic bases have undergone ring opening. The reaction most likely results from coordination of trialkylsilyl triflates to the beta-ketoester in 1, forming an ion-pair intermediate 6. The adduct 6 is so strongly electron-deficient that it can electrophilically attack the nonbonding nitrogen electron pairs in DBU and DBN.}, keywords = {DERIVATIVES, SUBSTITUTION}, isbn = {0040-4020}, url = {://A1996TL97400013}, author = {Ma, L. F. and Dolphin, D.} } @article {3663, title = {A remarkable multiple rearrangement process in the bromination of endo-3-bromo-4-methylcamphor: Intermediates for triterpenoid synthesis}, journal = {Tetrahedron}, volume = {52}, number = {47}, year = {1996}, note = {ISI Document Delivery No.: VT272Times Cited: 2Cited Reference Count: 36}, month = {Nov}, pages = {14661-14672}, type = {Article}, abstract = {The remarkable transformation of endo-3-bromo-4-methylcamphor (9) to endo-3,9-dibromo-4-(bromomethyl)camphor (11) forms the basis of a new approach to intermediates for the synthesis of lanostane triterpenoids, euphane triterpenoids and 14 alpha-methyl steroids. Copyright (C) 1996 Elsevier Science Ltd}, keywords = {4-METHYLCAMPHOR, CAMPHOR, CYCLIZATION, DERIVATIVES, ENANTIOSPECIFIC SYNTHESIS, NATURAL PRODUCT SYNTHESIS, ORGANIC-SYNTHESIS, ROUTE, STEROID-SYNTHESIS, SYNTHONS}, isbn = {0040-4020}, url = {://A1996VT27200003}, author = {Ferguson, C. G. and Money, T. and Pontillo, J. and Whitelaw, P. D. M. and Wong, M. K. C.} } @article {3865, title = {The safe and convenient preparation of bis(fluorosulfuryl) peroxide (S2O6F2) on a large scale}, journal = {Journal of Fluorine Chemistry}, volume = {76}, number = {1}, year = {1996}, note = {ISI Document Delivery No.: TW373Times Cited: 18Cited Reference Count: 20}, month = {Jan}, pages = {83-89}, type = {Article}, abstract = {The design and construction of a catalytic reactor (AgF2 on copper turnings as support) for the fluorination of SO3 in a flow reaction to produce bis(fluorosulfuryl) peroxide (S2O6F2) are described in detail. An operating procedure is developed that allows the production of S2O6F2 in substantial quantities (80-120 g h(-1)) and avoids the accidental production of fluorine fluorosulfate (FOSO2F) as a hazardous byproduct. Also described are purification methods and disposal procedures for highly reactive byproducts (F-2 or FOSO2F) in a safe and environmentally friendly manner, as well as the long-term storage of S2O6F2.}, keywords = {AgF2 catalysis, bis(fluorosulfuryl), catalytic fluorination, DERIVATIVES, flow reactor design, FLUOROSULFATE, FOSO2F, peroxide synthesis}, isbn = {0022-1139}, url = {://A1996TW37300016}, author = {Zhang, D. and Wang, C. and Mistry, F. and Powell, B. and Aubke, F.} } @article {3754, title = {Stereoselective synthesis of new chlorophyll A related antioxidants isolated from marine organisms}, journal = {Journal of Organic Chemistry}, volume = {61}, number = {7}, year = {1996}, note = {ISI Document Delivery No.: UD653Times Cited: 39Cited Reference Count: 37}, month = {Apr}, pages = {2501-2510}, type = {Article}, abstract = {A new class of natural antioxidants, chlorophyll a related chlorins 3, 4(S), 4(R), 5(R), 6, 7, 8, and 9, have been synthesized from a chlorophyll a degradation product, pheophorbide a methyl ester (1). Claisen-type intramolecular condensation of pyropheophorbide a methyl ester (2) afforded the common intermediate enol 3. Chlorin 1 and enol 3 have a propensity to undergo exocyclic ring opening by ionic bases. The organic base DBU was found to be an efficient reagent for promoting the asymmetric hydroxylation of these chlorins, using N-sulfonyloxaziridines, without cleavage of the exocyclic rings. Model studies for hydroxylactonization have shown that periodate oxidation of hydroxy ketone 10 stereoselectively and predominantly forms hydroxy lactone 17(S). Periodate oxidation of alpha-hydroxy 1,3-diketone 4(R) and/or 4(S) to furnish hydroxy lactone 5(R) and diketone 7 was found out to be regioselective, and the site of reaction depends on the appropriate choice of reaction media. H-1 NMR spectra have provided information on the absolute configuration of diastereomers at the C-13(2) or C-15(1) position.}, keywords = {2-SULFONYLOXAZIRIDINES, CHEMISTRY, COMPOUND, DERIVATIVES, enol, HYDROXYLATION, ORIGINS, RCI, RUDITAPES-PHILIPPINARUM}, isbn = {0022-3263}, url = {://A1996UD65300039}, author = {Ma, L. F. and Dolphin, D.} } @article {3866, title = {Superacid anions: Crystal and molecular structures of oxonium undecafluorodiantimonate(V), [H3O][Sb2F11], cesium fluorosulfate, CsSO3F, cesium hydrogen bis(fluorosulfate), Cs[H(SO3F)(2)], cesium tetrakis(fluorosulfato)aurate(III), Cs[Au(SO3F)(4)], cesium}, journal = {Inorganic Chemistry}, volume = {35}, number = {21}, year = {1996}, note = {ISI Document Delivery No.: VL611Times Cited: 31Cited Reference Count: 90}, month = {Oct}, pages = {6113-6130}, type = {Article}, abstract = {{In order to understand the reasons for the low nucleophilicity of superacid anions, a systematic, comparative study of six superacid anions by single-crystal X-ray diffraction is undertaken. From magic acid, HSO3F-SbF5, surprisingly, single crystals of oxonium undecafluorodiantimonate(V), [H3O][Sb2F11], 1, are obtained. In the remaining five salts the cesium ion, Cs+, is used as the countercation. Both CsSO3F, 2, and its solvate Cs[H(SO3F)(2)], 3, are derived from the Bronsted superacid HSO3F. The conjugate noble metal superacid systems HSO3F-Au(SO3F)(3) and HSO3F-Pt(SO3F)(4) provide cesium tetrakis(fluorosulfato)aurate(III) Cs[Au(SO3F)(4)], 4, and cesium hexakis (fluorosulfato)platinate(IV) Cs-2[Pt(SO3F)(6)], 5. Cesium hexakis (fluorosulfato)antimonate(V) Cs[Sb(SO3F)(6)], 6, whose synthesis is described here in detail, provides evidence for the possible existence of a new conjugate superacid system, HSO3F-Sb(SO3F)(5). Crystals of [H3O][Sb2F11] (1, H3F11OSb2) are orthorhombic}, keywords = {ACIDS, BEHAVIOR, CATIONS, CONSTANTS, DERIVATIVES, FLUORIDE, FLUOROSULFATE, GOLD(III), TRIS(FLUOROSULFATE), VIBRATIONAL-SPECTRA, WEAKLY COORDINATING ANIONS}, isbn = {0020-1669}, url = {://A1996VL61100024}, author = {Zhang, D. L. and Rettig, S. J. and Trotter, J. and Aubke, F.} } @article {3866, title = {Superacid anions: Crystal and molecular structures of oxonium undecafluorodiantimonate(V), [H3O][Sb2F11], cesium fluorosulfate, CsSO3F, cesium hydrogen bis(fluorosulfate), Cs[H(SO3F)(2)], cesium tetrakis(fluorosulfato)aurate(III), Cs[Au(SO3F)(4)], cesium}, journal = {Inorganic Chemistry}, volume = {35}, number = {21}, year = {1996}, note = {ISI Document Delivery No.: VL611Times Cited: 31Cited Reference Count: 90}, month = {Oct}, pages = {6113-6130}, type = {Article}, abstract = {{In order to understand the reasons for the low nucleophilicity of superacid anions, a systematic, comparative study of six superacid anions by single-crystal X-ray diffraction is undertaken. From magic acid, HSO3F-SbF5, surprisingly, single crystals of oxonium undecafluorodiantimonate(V), [H3O][Sb2F11], 1, are obtained. In the remaining five salts the cesium ion, Cs+, is used as the countercation. Both CsSO3F, 2, and its solvate Cs[H(SO3F)(2)], 3, are derived from the Bronsted superacid HSO3F. The conjugate noble metal superacid systems HSO3F-Au(SO3F)(3) and HSO3F-Pt(SO3F)(4) provide cesium tetrakis(fluorosulfato)aurate(III) Cs[Au(SO3F)(4)], 4, and cesium hexakis (fluorosulfato)platinate(IV) Cs-2[Pt(SO3F)(6)], 5. Cesium hexakis (fluorosulfato)antimonate(V) Cs[Sb(SO3F)(6)], 6, whose synthesis is described here in detail, provides evidence for the possible existence of a new conjugate superacid system, HSO3F-Sb(SO3F)(5). Crystals of [H3O][Sb2F11] (1, H3F11OSb2) are orthorhombic}, keywords = {ACIDS, BEHAVIOR, CATIONS, CONSTANTS, DERIVATIVES, FLUORIDE, FLUOROSULFATE, GOLD(III), TRIS(FLUOROSULFATE), VIBRATIONAL-SPECTRA, WEAKLY COORDINATING ANIONS}, isbn = {0020-1669}, url = {://A1996VL61100024}, author = {Zhang, D. L. and Rettig, S. J. and Trotter, J. and Aubke, F.} } @article {3843, title = {Synthesis, molecular structure, and vibrational spectra of mer-tris(carbonyl)iridium(III)fluorosulfate, mer-Ir(CO)(3)(SO3F)(3)}, journal = {Inorganic Chemistry}, volume = {35}, number = {5}, year = {1996}, note = {ISI Document Delivery No.: TY260Times Cited: 21Cited Reference Count: 36}, month = {Feb}, pages = {1279-1285}, type = {Article}, abstract = {{Addition of carbon monoxide (0.5-2 atm) to iridium(III) fluorosulfate, Ir(SO3F)(3), dissolved in HSO3F over 4 days and at 60 degrees C, results in the quantitative formation of tris(carbonyl)iridium(III) fluorosulfate Ir(CO)(3)(SO3F)(3) Slow evaporation of the solvent produces single crystals of mer-Ir(CO)(3)(SO3F)(3). Crystal structure data for mer-Ir(CO)(3)(SO3F)(3): monoclinic, space group P2(1)/c}, keywords = {DERIVATIVES, FLUOROSULFATES, GOLD, palladium, SYSTEM, UNDECAFLUORODIANTIMONATE(V)}, isbn = {0020-1669}, url = {://A1996TY26000029}, author = {Wang, C. Q. and Lewis, A. R. and Batchelor, R. J. and Einstein, F. W. B. and Willner, H. and Aubke, F.} } @article {3643, title = {Synthesis of some phosphino- and arsinobenzenechromium tricarbonyl derivatives and metal carbonyl clusters}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {74}, number = {11}, year = {1996}, note = {ISI Document Delivery No.: WC124Times Cited: 6Cited Reference Count: 36}, month = {Nov}, pages = {2167-2181}, type = {Article}, abstract = {{The synthesis of a number of new phosphino- and arsinobenzenechromium tricarbonyl ligands ER(2)C(6)H(5)Cr(CO)(3) (ER(2) = PEt(2), PPr2i, PBu(2)(t), PPh(2), AsPh(2) AsMe(2)), ER[C6H5Cr(CO)(3)](2) (ER = PEt, PBu(t), PPh, AsPh) has been achieved by reacting lithium derivatives of benzenechromium tricarbonyl with appropriate chlorophosphines or iodoarsines. The spectroscopic properties of these ligands are described. The structure of (Pr2PC6H5Cr)-P-i(CO)(3) was determined by an X-ray crystallographic study. This is the first solid state structure to be reported for a phosphinobenzenechromium tricarbonyl derivative. The structures of four metal carbonyl cluster complexes were also determined. Crystals of (Pr2PC6H5Cr)-P-i(CO)(3) (3, C15H19CrO3P) are monoclinic, space group P2(1)/c}, keywords = {(BENZYNE)CHROMIUM, arsinobenzenechromium tricarbonyl derivatives, CHEMISTRY, COMPLEXES, CRYSTAL, DERIVATIVES, LIGAND-SUBSTITUTED DERIVATIVES, metal carbonyl clusters, OS3(CO)12, P(OCH2CF3)3, phosphinobenzenechromium tricarbonyl, RU3(CO)12, STEREOCHEMISTRY, structures, TRICARBONYL, X-ray structures}, isbn = {0008-4042}, url = {://A1996WC12400031}, author = {Cullen, W. R. and Rettig, S. J. and Zhang, H. L.} } @article {3581, title = {ANTIMONY(III) FLUORIDE FLUOROSULFATES - SYNTHESES AND MOLECULAR-STRUCTURES OF ANTIMONY(III) DIFLUORIDE FLUOROSULFATE [SBF2(SO3F)](X), ANTIMONY(III) FLUORIDE BIS(FLUOROSULFATE) [SBF(SO3F)(2)](X), AND ANTIMONY(III) TRIS(FLUOROSULFATE) [SB(SO3F)(3)](X)}, journal = {Inorganic Chemistry}, volume = {34}, number = {12}, year = {1995}, note = {ISI Document Delivery No.: RC424Times Cited: 7Cited Reference Count: 52}, month = {Jun}, pages = {3153-3164}, type = {Article}, abstract = {{Following unsuccessful attempts to confirm the existence of previously reported antimony(I) fluorosulfate, Sb(SO3F), the reaction of antimony and fluorosulfuric acid is reinvestigated and synthetic routes are developed that allow the preparation of polymeric [SbF2(SO3F)](x), [SbF(SO3F)(2)](x), and [Sb(SO3F)(3)](x). Recrystallization from fluorosulfuric acid is found to produce single crystals of all three materials, which are suitable for molecular structure determinations by single-crystal X-ray diffraction. Crystals of [SbF2(SO3F)](x) are orthorhombic}, keywords = {CRYSTAL-STRUCTURE, DERIVATIVES, MOSSBAUER, SPECTRA}, isbn = {0020-1669}, url = {://A1995RC42400005}, author = {Zhang, D. L. and Rettig, S. J. and Trotter, J. and Aubke, F.} } @article {3581, title = {ANTIMONY(III) FLUORIDE FLUOROSULFATES - SYNTHESES AND MOLECULAR-STRUCTURES OF ANTIMONY(III) DIFLUORIDE FLUOROSULFATE [SBF2(SO3F)](X), ANTIMONY(III) FLUORIDE BIS(FLUOROSULFATE) [SBF(SO3F)(2)](X), AND ANTIMONY(III) TRIS(FLUOROSULFATE) [SB(SO3F)(3)](X)}, journal = {Inorganic Chemistry}, volume = {34}, number = {12}, year = {1995}, note = {ISI Document Delivery No.: RC424Times Cited: 7Cited Reference Count: 52}, month = {Jun}, pages = {3153-3164}, type = {Article}, abstract = {{Following unsuccessful attempts to confirm the existence of previously reported antimony(I) fluorosulfate, Sb(SO3F), the reaction of antimony and fluorosulfuric acid is reinvestigated and synthetic routes are developed that allow the preparation of polymeric [SbF2(SO3F)](x), [SbF(SO3F)(2)](x), and [Sb(SO3F)(3)](x). Recrystallization from fluorosulfuric acid is found to produce single crystals of all three materials, which are suitable for molecular structure determinations by single-crystal X-ray diffraction. Crystals of [SbF2(SO3F)](x) are orthorhombic}, keywords = {CRYSTAL-STRUCTURE, DERIVATIVES, MOSSBAUER, SPECTRA}, isbn = {0020-1669}, url = {://A1995RC42400005}, author = {Zhang, D. L. and Rettig, S. J. and Trotter, J. and Aubke, F.} } @article {3322, title = {AN ASYMMETRIC CARCEPLEX AND NEW CRYSTAL-STRUCTURE YIELD INFORMATION REGARDING A 1-MILLION-FOLD TEMPLATE EFFECT}, journal = {Journal of Organic Chemistry}, volume = {60}, number = {5}, year = {1995}, note = {ISI Document Delivery No.: QL605Times Cited: 48Cited Reference Count: 50}, month = {Mar}, pages = {1207-1213}, type = {Article}, abstract = {We report the incorporation of methyl {\textquoteright}{\textquoteright}feet{\textquoteright}{\textquoteright} as pendant groups in cavitands and carceplexes and their use in the creation of an asymmetric carceplex and the facilitation of the determination of the crystal structure of a carceplex. From the asymmetric carceplex, we have determined a 19 kcal/mol energy barrier to rotation of the guest pyrazine about the host{\textquoteright}s pseudo-C-2 axes, which demonstrates a high degree of complementarity between the shell of the carceplex and the guest pyrazine. The crystal structure reveals the extensive conjugation of the aryl ethers into the aromatic rings of the host when pyrazine is the guest. This result helps explain why pyrazine is, to date, the best template for the reaction to form the carceplex and thus provides insight to the powerful template effect that is the hallmark of this carceplex reaction. Thus, the investigation of this template effect provides a sensitive probe into noncovalent interactions in general and may be useful in the understanding of recognition in both natural systems such as enzyme/substrate complexes and in non-natural systems such as designed self-assembling structures.}, keywords = {4 PORTALS, CAPTURE, CAVITANDS, CONSTRICTIVE BINDING, DERIVATIVES, HEMICARCERAND, HOST-GUEST COMPLEXATION, RELEASE}, isbn = {0022-3263}, url = {://A1995QL60500025}, author = {Fraser, J. R. and Borecka, B. and Trotter, J. and Sherman, J. C.} } @article {3322, title = {AN ASYMMETRIC CARCEPLEX AND NEW CRYSTAL-STRUCTURE YIELD INFORMATION REGARDING A 1-MILLION-FOLD TEMPLATE EFFECT}, journal = {Journal of Organic Chemistry}, volume = {60}, number = {5}, year = {1995}, note = {ISI Document Delivery No.: QL605Times Cited: 48Cited Reference Count: 50}, month = {Mar}, pages = {1207-1213}, type = {Article}, abstract = {We report the incorporation of methyl {\textquoteright}{\textquoteright}feet{\textquoteright}{\textquoteright} as pendant groups in cavitands and carceplexes and their use in the creation of an asymmetric carceplex and the facilitation of the determination of the crystal structure of a carceplex. From the asymmetric carceplex, we have determined a 19 kcal/mol energy barrier to rotation of the guest pyrazine about the host{\textquoteright}s pseudo-C-2 axes, which demonstrates a high degree of complementarity between the shell of the carceplex and the guest pyrazine. The crystal structure reveals the extensive conjugation of the aryl ethers into the aromatic rings of the host when pyrazine is the guest. This result helps explain why pyrazine is, to date, the best template for the reaction to form the carceplex and thus provides insight to the powerful template effect that is the hallmark of this carceplex reaction. Thus, the investigation of this template effect provides a sensitive probe into noncovalent interactions in general and may be useful in the understanding of recognition in both natural systems such as enzyme/substrate complexes and in non-natural systems such as designed self-assembling structures.}, keywords = {4 PORTALS, CAPTURE, CAVITANDS, CONSTRICTIVE BINDING, DERIVATIVES, HEMICARCERAND, HOST-GUEST COMPLEXATION, RELEASE}, isbn = {0022-3263}, url = {://A1995QL60500025}, author = {Fraser, J. R. and Borecka, B. and Trotter, J. and Sherman, J. C.} } @article {3566, title = {{KINETIC AND MECHANISTIC ASPECTS OF SULFUR ABSTRACTION FROM PD(2)X(2)(MU-S)(MU-DPM)(2) USING DPM OR DPMME [X=HALIDE}, journal = {Inorganic Chemistry}, volume = {34}, number = {9}, year = {1995}, note = {ISI Document Delivery No.: QV824Times Cited: 23Cited Reference Count: 30}, month = {Apr}, pages = {2278-2286}, type = {Article}, abstract = {Solution kinetic and mechanistic studies were performed on the abstraction of sulfur from Pd(2)X(2)(mu-S)(mu-dpm)(2) [X = Cl (2a), Br (2b), I(2c)] using bis(diphenylphosphino)methane (dpm) to give, respectively, Pd(2)X(2)(dpm)(2) [X = Cl (1a), Br (1b), I (1c)] and dpm(S). The reaction is first-order in both 2 and dpm with the reactivity trend in CHCl3 being X = Cl > Br > I. The activation parameters for the chloride system are Delta H-double dagger = 41 +/- 3 kJ mol(-1) and Delta S-double dagger = -127 +/- 10 J K-1 mol(-1), and for the bromide, Delta H-double dagger = 38 +/- 1 kJ mol(-1) and Delta S-double dagger = -144 +/- 4 J K-1 mol(-1), showing the entropy term is dominant in governing reactivity. Low-temperature NMR studies did not reveal the presence of observable intermediates. 2b and 1b undergo rapid diphosphine ligand exchange with dpm-d(2); with 2b, prior to any S-abstraction, Pd2Br2(mu-S)(dpm)(dpm-d(2)) (7b) and Pd2Br2(mu-S)(dpm-d(2))(2) (8b) are present, while Pd2Br2(dpm)(dpm-d(2)) (3b) and Pd2Br2(dpm-d(2))(2) (4b) are formed, as well as 1b and dpm(S)-d(2), in the abstraction reaction of 2b with dpm-d(2). The distribution of products is close to statistical on the basis of the stoichiometries of the reactants. Reaction of 2b with 1,1{\textquoteright}-bis(diphenylphosphino)ethane (dpmMe) proceeds in an analogous way generating 1b, Pd2Br2(dpm)(dpmMe) (5b), Pd2Br2(dpmMe)(2) (6b), dpm(S), and dpmMe(S). In contrast, 1b undergoes slow diphosphine ligand exchange with dpmMe to form 5b and 6b; 2b undergoes no ligand exchange with dpmMe prior to the S-abstraction reaction. The findings are rationalized in terms of postulated intermediates and transition states that include formulations with three equivalent diphosphines. No sulfur abstraction occurs on treating 2b with PPh(3), PPh(2)Me, or Ph(2)P(CH2)(3)PPh(2).}, keywords = {BIS(DIPHENYLPHOSPHINO)METHANE DPM, BIS-PHOSPHORUS LIGANDS, COMPLEXES, CRYSTAL-STRUCTURE, DERIVATIVES, DINUCLEAR PALLADIUM(I), HYDROGEN-SULFIDE, METAL-METAL BONDS, MONONUCLEAR, Pd(I)}, isbn = {0020-1669}, url = {://A1995QV82400007}, author = {Wong, T. Y. H. and Barnabas, A. F. and Sallin, D. and James, Brian R.} } @article {3272, title = {The kinetics and energetics of formation of a molecular hydrogen complex involving a dinuclear ruthenium(II) centre}, journal = {Inorganica Chimica Acta}, volume = {240}, number = {1-2}, year = {1995}, note = {ISI Document Delivery No.: TV742Times Cited: 9Cited Reference Count: 32}, month = {Dec}, pages = {419-425}, type = {Article}, abstract = {The reversible equilibrium conversion under H-2 of [RuCl(dppb) (mu-Cl)](2) (1) to generate (eta(2)-H-2) (dppb) (mu-Cl)(3)RUCl( dppb) in CH2Cl2 (dppb = Ph(2)P(CH2)(4)PPh(2)) has been studied at 0-25 degrees C by UV-Vis and (31)p{H-1} NMR spectroscopy, and by stopped-how kinetics; the equilibrium constant and corresponding thermodynamic parameters, and the forward and reverse rate constants at 25 degrees C have been determined. A measured Delta H degrees value of similar to 0 kj mol(-1) allows for an estimation of an exothermicity of similar to 60 kj mol(-1) for binding an eta(2)-H-2 at an Ru(II) centre; a Delta S degrees value of similar to 60 J mol(-1) K-1 indicates that in solution 1 contains coordinated CH2Cl2. The kinetic and thermodynamic data are compared to those obtained from a previously studied hydrogenation of styrene catalyzed by 1. Preliminary findings on related systems containing Ph(2)P(CH2)(3)PPh(2) and (C6H11)(2)P(CH2)(4)P(C6H11)(2) are also noted.}, keywords = {BINDING, DERIVATIVES, DIHYDROGEN, dihydrogen complexes, LIGANDS, MECHANISTIC ASPECTS, NITROGEN, PHOSPHINE COMPLEXES, ruthenium complexes, SELECTIVE HYDROGENATION}, isbn = {0020-1693}, url = {://A1995TV74200054}, author = {Chau, Deky and James, Brian R.} } @article {3330, title = {THE NOVEL PHOTOCHEMICAL BEHAVIOR OF TRIPTYCENE-1,4-QUINONE}, journal = {Tetrahedron Letters}, volume = {36}, number = {12}, year = {1995}, note = {ISI Document Delivery No.: QP020Times Cited: 8Cited Reference Count: 10}, month = {Mar}, pages = {2025-2028}, type = {Article}, abstract = {Triptycene-1,4-quinone (1) reacts photochemically in solution to give different products depending on the solvent employed and on the presence or absence of oxygen. The structures of the photoproducts have been elucidated by spectroscopic methods, independent synthesis and single crystal X-ray diffractometry, and possible mechanistic pathways leading to their formation are presented and discussed. Unexpectedly, quinone 1 was found to be photochemically inert in the crystalline state. The X-ray crystal structure of 1 reveals the probable reason for this behavior.}, keywords = {10-DIHYDRO-9, 10-ORTHO-BENZENOANTHRACENE-1, 4-DIONES, 9, ABSTRACTION, DERIVATIVES, INTRAMOLECULAR CHARGE-TRANSFER, TRANSITION}, isbn = {0040-4039}, url = {://A1995QP02000014}, author = {Fu, T. Y. and Gamlin, J. N. and Olovsson, G. and Scheffer, J. R. and Trotter, J. and Young, D. T.} } @article {3330, title = {THE NOVEL PHOTOCHEMICAL BEHAVIOR OF TRIPTYCENE-1,4-QUINONE}, journal = {Tetrahedron Letters}, volume = {36}, number = {12}, year = {1995}, note = {ISI Document Delivery No.: QP020Times Cited: 8Cited Reference Count: 10}, month = {Mar}, pages = {2025-2028}, type = {Article}, abstract = {Triptycene-1,4-quinone (1) reacts photochemically in solution to give different products depending on the solvent employed and on the presence or absence of oxygen. The structures of the photoproducts have been elucidated by spectroscopic methods, independent synthesis and single crystal X-ray diffractometry, and possible mechanistic pathways leading to their formation are presented and discussed. Unexpectedly, quinone 1 was found to be photochemically inert in the crystalline state. The X-ray crystal structure of 1 reveals the probable reason for this behavior.}, keywords = {10-DIHYDRO-9, 10-ORTHO-BENZENOANTHRACENE-1, 4-DIONES, 9, ABSTRACTION, DERIVATIVES, INTRAMOLECULAR CHARGE-TRANSFER, TRANSITION}, isbn = {0040-4039}, url = {://A1995QP02000014}, author = {Fu, T. Y. and Gamlin, J. N. and Olovsson, G. and Scheffer, J. R. and Trotter, J. and Young, D. T.} } @article {3241, title = {RUTHENIUM COMPLEXES CONTAINING TERTIARY PHOSPHINES AND IMIDAZOLE OR 2,2{\textquoteright}-BIPYRIDINE LIGANDS}, journal = {Inorganica Chimica Acta}, volume = {230}, number = {1-2}, year = {1995}, note = {ISI Document Delivery No.: QN719Times Cited: 26Cited Reference Count: 39}, month = {Mar}, pages = {111-117}, type = {Article}, abstract = {{Complexes RuCl3(PPh(3))L(2) (L=MeIm (1a), Im (1b)) and [RuCl2(PPh(3))(2)(bipy)]Cl . 4H(2)O (2) have been synthesized via the ruthenium(III) precursor RuCl3(PPh(3))(2) (DMA), and characterized, including an X-ray structural analysis for 1a (MeIm=N-methylimidazole}, keywords = {BIPYRIDINE COMPLEXES, CRYSTAL, crystal structures, DERIVATIVES, HYDROGEN, IMIDAZOLE COMPLEXES, ruthenium complexes, TERTIARY PHOSPHINE COMPLEXES, X-ray structure}, isbn = {0020-1693}, url = {://A1995QN71900015}, author = {Batista, A. A. and Polato, E. A. and Queiroz, S. L. and Nascimento, O. R. and James, Brian R. and Rettig, S. J.} } @article {2962, title = {ANOMALOUS DOUBLE CYCLIZATION REACTIONS OF BETA-FORMYLPORPHYRINS}, journal = {Journal of Organic Chemistry}, volume = {59}, number = {26}, year = {1994}, note = {ISI Document Delivery No.: QA492Times Cited: 49Cited Reference Count: 23}, month = {Dec}, pages = {7976-7985}, type = {Article}, abstract = {Treatment of nickel(II) and copper(II) complexes of 2(beta)-formyl-meso-tetraphenylporphyrins with strong acid results in intramolecular cyclization involving the carbonyl carbon and the ortho-phenyl position leading to naphthoporphyrin derivatives. However, when electron-releasing groups are present at the m-phenyl positions, a second cyclization occurs involving the 3(beta) position and the ortho position of the adjacent phenyl ring to give an additional fused ring.}, keywords = {DERIVATIVES, PHOTOSENSITIZERS, porphyrins}, isbn = {0022-3263}, url = {://A1994QA49200011}, author = {Barloy, L. and Dolphin, D. and Dupre, D. and Wijesekera, T. P.} } @article {3148, title = {A CONVENIENT PROCEDURE FOR THE EFFICIENT PREPARATION OF ALKYL (Z)-3-IODO-2-ALKENOATES}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {72}, number = {8}, year = {1994}, note = {ISI Document Delivery No.: PE254Times Cited: 53Cited Reference Count: 29}, month = {Aug}, pages = {1816-1819}, type = {Article}, abstract = {Reaction of alkyl 2-alkynoates with sodium iodide (1.6-5.5 equiv.) in acetic acid (6.2-13 equiv.) at 115 degrees C provides good to excellent yields of the corresponding alkyl (Z)-3-iodo-2-alkenoates.}, keywords = {ACID, ALLYLIC ALCOHOLS, DERIVATIVES, PROPIOLIC, STEREOSPECIFIC HYDROHALOGENATION REACTION}, isbn = {0008-4042}, url = {://A1994PE25400009}, author = {Piers, E. and Wong, T. and Coish, P. D. and Rogers, C.} } @article {3067, title = {CRYSTAL-STRUCTURE AND PHOTOCHEMISTRY OF DIMETHYL 1,4-DIHYDRO-1,4,5,8-TETRAMETHYL-1,4-ETHENONAPHTHALENE-2,3-DICARBOXYLATE}, journal = {Acta Crystallographica Section B-Structural Science}, volume = {50}, year = {1994}, note = {ISI Document Delivery No.: PL238Times Cited: 1Cited Reference Count: 9Part 5}, month = {Oct}, pages = {597-600}, type = {Article}, abstract = {{The photochemical rearrangement of a bridgehead-methylated 1,4-ethenonaphthalene has been studied by crystal structure analyses of (1b) and two of its photoproducts (2b and 3b). Crystal data: T = 295 K, Cu K alpha}, keywords = {1, 3-DICARBOXYLATE, 4-DIHYDRO-1, 4-ETHENONAPHTHALENE-2, DERIVATIVES}, isbn = {0108-7681}, url = {://A1994PL23800013}, author = {Jones, R. and Scheffer, J. R. and Trotter, J. and Yap, M.} } @article {3067, title = {CRYSTAL-STRUCTURE AND PHOTOCHEMISTRY OF DIMETHYL 1,4-DIHYDRO-1,4,5,8-TETRAMETHYL-1,4-ETHENONAPHTHALENE-2,3-DICARBOXYLATE}, journal = {Acta Crystallographica Section B-Structural Science}, volume = {50}, year = {1994}, note = {ISI Document Delivery No.: PL238Times Cited: 1Cited Reference Count: 9Part 5}, month = {Oct}, pages = {597-600}, type = {Article}, abstract = {{The photochemical rearrangement of a bridgehead-methylated 1,4-ethenonaphthalene has been studied by crystal structure analyses of (1b) and two of its photoproducts (2b and 3b). Crystal data: T = 295 K, Cu K alpha}, keywords = {1, 3-DICARBOXYLATE, 4-DIHYDRO-1, 4-ETHENONAPHTHALENE-2, DERIVATIVES}, isbn = {0108-7681}, url = {://A1994PL23800013}, author = {Jones, R. and Scheffer, J. R. and Trotter, J. and Yap, M.} } @article {3007, title = {EXCESS PARTIAL MOLAR VOLUMES AND THERMAL EXPANSIVITIES IN THE WATER-RICH REGION OF AQUEOUS 2-BUTANONE}, journal = {Journal of Solution Chemistry}, volume = {23}, number = {2}, year = {1994}, note = {ISI Document Delivery No.: NB508Times Cited: 8Cited Reference Count: 22Symposium in Honor of Donald Patterson on His 65th Birthday, at the 76th Congress of the Canadian-Society-for-ChemistryMAY 31-JUN 03, 1993SHERBROOKE, CANADACANADIAN SOC CHEM}, month = {Feb}, pages = {339-349}, type = {Proceedings Paper}, abstract = {Excess partial molar volumes of 2-butanone V(m)E(B) and thermal expansivities alpha(p) were measured in the water-rich region of aqueous 2-butanone. The composition derivatives of both quantities showed anomalies at about X(B) = 0.033 (x(B) is the mole fraction of B). (partial derivative V(m)E(B)/partial derivative n(B))p,T,nW showed a step anomaly, while (partial derivative alpha(p)/partial derivatives n(B))p,T,nw exhibited a peak anomaly. The compositions at which these anomalies occurred match those of the step anomalies observed earlier in (partial derivative H(m)E(B)/partial derivative n(B))p,T,nW and (partial derivative S(m)E(B)/partial derivative n(B))p,T,nW in aqueous 2-butanone. These results are discussed in comparison with those obtained previously for aqueous 2-butoxyethanol.}, keywords = {2-BUTANONE, 2-BUTOXYETHANOL, 25-DEGREES-C, ANOMALIES IN 3RD DERIVATIVES, AQUEOUS, DERIVATIVES, ENTHALPIES, EXCESS PARTIAL MOLAR VOLUMES, fluctuations, FREE-ENERGIES, HEAT-CAPACITIES, MIXING SCHEME, OF GIBBS FREE ENERGY, TERT-BUTANOL MIXTURES, THERMAL EXPANSIVITIES, TRANSITION, TRANSITION OF MIXING SCHEME}, isbn = {0095-9782}, url = {://A1994NB50800016}, author = {Davies, J. V. and Fooks, R. and Koga,Yoshikata} } @article {3118, title = {PORPHYRIN CHEMISTRY PERTAINING TO THE DESIGN OF ANTICANCER DRUGS .2. THE SYNTHESIS AND IN-VITRO TESTS OF WATER-SOLUBLE PORPHYRINS CONTAINING, IN THE MESO POSITIONS, THE FUNCTIONAL-GROUPS - 4-METHYLPYRIDINIUM, OR 4-SULFONATOPHENYL, IN COMBINATION WITH PHEN}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {72}, number = {12}, year = {1994}, note = {ISI Document Delivery No.: QC582Times Cited: 38Cited Reference Count: 46}, month = {Dec}, pages = {2447-2457}, type = {Article}, abstract = {Water-soluble, meso-substituted porphyrins are synthesized by sulfonation or methylation of the phenyl or pyridyl groups, respectively, of some non-water-soluble functionalized porphyrins that we have recently synthesized (Can. J. Chem. 72, 1894 (1994)). Twelve anionic sulfonated and seven cationic methylpyridinium porphyrins, usually containing other functional groups (phenyl, pyridyl, nitro- and amino-phenyl), are reported on. Twelve of these porphyrins are new, and all nineteen porphyrins are characterized by H-1 NMR. UV-VIS data are presented for the isolated porphyrins, while mass spectral data are noted for selected compounds. Partition coefficients of the porphyrins in octanol-water, and the accumulation of the porphyrins in HT-29 cells of a human-cancer tumor, were measured and both were inversely related to the charges of the porphyrins. The 11 porphyrins soluble in biological buffer solutions are basically nontoxic to Chinese hamster ovary (CHO) cells in oxic or hypoxic conditions or to aerobic HT-29 cells at the 100 mu M concentration used (which is sometimes limited by solubility). No significant X-ray radiosensitization was observed for selected porphyrins toward CHO cells at the 100 mu M concentrations used, but some photosensitized cell kill (using 630 nm light) was observed using the disodium salt of 5,10-bis(4-pyridyl)-15,20-bis(4-sulfonatophenyl)porphyrin (24).}, keywords = {AGGREGATION, CATIONIC PORPHYRIN, CELLULAR DELIVERY, COMPLEXES, DERIVATIVES, DNA, ENHANCEMENT, INTERCALATION, METALLOPORPHYRINS, PHOTOSENSITIZATION}, isbn = {0008-4042}, url = {://A1994QC58200011}, author = {Meng, G. G. and James, Brian R. and Skov, K. A. and Korbelik, M.} } @article {3064, title = {THE SYNTHESES AND VIBRATIONAL-SPECTRA OF BIS(CARBONYL)PLATINUM(II) FLUOROSULFATE, PT(CO)2(SO3F)2, AND BIS(CARBONYL)PALLADIUM(II) FLUOROSULFATE, PD(CO)2(SO3F)2}, journal = {Journal of Fluorine Chemistry}, volume = {66}, number = {2}, year = {1994}, note = {ISI Document Delivery No.: MX367Times Cited: 26Cited Reference Count: 43}, month = {Feb}, pages = {159-166}, type = {Article}, abstract = {Reductive carbonylation of platinum(IV) tetrakis(fluorosulfate), Pt(SO3F)4, in fluorosulfuric acid at 80-degrees-C with a CO pressure of 1-2 atm resulted in the quantitative formation of creamy white bis(carbonyl)platinum(II) fluorosulfate, Pt(CO)2(SO3F)2. The corresponding bis(carbonyl)palladium(II) fluorosulfate, Pd(CO)2(SO3F)2, has been formed from solid Pd(II)Pd(IV)(SO3F)6 at room temperature and a CO pressure of 0.5 atm as a yellow solid that was thermally stable up to 117-degrees-C. Both compounds gave nearly identical IR and Raman spectra, which suggests a cis-square-planar configuration. The average CO stretching frequencies were at 2217 and 2201 cm-1 for Pd(CO)2(SO3F)2 and Pt(CO)2(SO3F)2, respectively. They are unusually high and suggest substantially reduced pi-back-donation. Pd(CO)2(SO3F)2 is the first example of a thermally stable mononuclear bis(carbonyl) derivative of dipositive palladium.}, keywords = {CARBONYL-COMPLEXES, DERIVATIVES, GOLD(III) FLUOROSULFATE, ION, LATE TRANSITION-ELEMENTS, PALLADIUM(II)}, isbn = {0022-1139}, url = {://A1994MX36700013}, author = {Hwang, G. and Wang, C. and Bodenbinder, M. and Willner, H. and Aubke, F.} } @article {2778, title = {REACTIVITY OF THE LEWIS-ACIDS CP-ASTERISK-M(NO)(CH2CME3)CL [M = MO, W] AND RELATED COMPLEXES}, journal = {Organometallics}, volume = {12}, number = {7}, year = {1993}, note = {ISI Document Delivery No.: LU682Times Cited: 26Cited Reference Count: 43}, month = {Jul}, pages = {2714-2725}, type = {Article}, abstract = {{Treatments of Cp*M(NO)Cl2 [Cp* = eta5-C5Me5; M = Mo, W] with 0.5 equiv of (Me3CCH2)2Mg.X(dioxane) in THF at low temperatures affords the monoalkylated complexes, Cp*M(NO)(CH2CMe3)Cl (1, 1{\textquoteright}). Exposure to a second 0.5 equiv of (Me3CCH2)2Mg.X(dioxane) at higher temperatures produces the dialkyl complexes, Cp*M(NO)(CH2CMe3)2 (2,2{\textquoteright}). Utilizing the two series of Cp*M(NO)Cl2, Cp*M(NO)(CH2CMe3)Cl and Cp*M(NO)(CH2CMe3)2 complexes, the relative electron deficiencies in these 16-electron complexes can be assessed spectroscopically and electrochemically. Without exception, the Mo complexes are the stronger Lewis acids. Also, the mononeopentyl derivatives for both metals are more reactive toward a variety of substrates than are their bis(neopentyl) analogues. Complexes 1 and 1{\textquoteright} serve as precursors to mixed alkyl and alkyl aryl complexes (3, 3{\textquoteright}, 4, 4{\textquoteright}) and yield metal-centered adducts with PMe3 and pyridine (5, 5{\textquoteright}, 6, 6{\textquoteright}). CO and CNCMe3 readily insert into the M-C bonds of 1 and 1{\textquoteright}. The insertion products, Cp*M(NO)(C{E}CH2CMe3)Cl (7, 7{\textquoteright}}, keywords = {ALKYL, C-H, CARBONYLATION, CONVERSION, DERIVATIVES, H ACTIVATION REACTIONS, MIGRATORY INSERTION, MOLYBDENUM, ORGANOMETALLIC NITROSYL CHEMISTRY, TUNGSTEN}, isbn = {0276-7333}, url = {://A1993LU68200046}, author = {Debad, J. D. and Legzdins,Peter and Rettig, S. J. and Veltheer, J. E.} } @article {2871, title = {SYNTHESES OF 2-DEOXY-2-FLUORO MONOSACCHARIDE AND OLIGOSACCHARIDE GLYCOSIDES FROM GLYCALS AND EVALUATION AS GLYCOSIDASE INHIBITORS}, journal = {Carbohydrate Research}, volume = {249}, number = {1}, year = {1993}, note = {ISI Document Delivery No.: MD387Times Cited: 41Cited Reference Count: 34}, month = {Oct}, pages = {77-90}, type = {Article}, abstract = {Several fluorinated oligosaccharides, including 2-deoxy-2-fluoro derivatives of cellobiose, maltose, and maltotriose were synthesized by the action of fluorine or acetyl hypofluorite on the corresponding glycal peracetates. Temperature effects on the stereoselectivities of these reactions were examined. Addition of acetyl hypofluorite to several 2-substituted glycals in the gluco or galacto series gave 2,2-disubstituted arabino- or lyxo-hexose derivatives; 3,4,6-tri-O-acetyl-2-fluoro-D-glucal or the analogous galactal yielded 2-deoxy-2,2-difluoro arabino- or lyxo-hexose peracetates, whereas 2-acetoxy-3,4,6-tri-O-acetyl-D-glucal or the analogous galactal gave 2(R)-2-acetoxy-2-fluoro-arabino- or lyxo-hexose peracetates, respectively. 2-Acetamido-3,4,6-tri-O-acetyl-D-glucal gave 2(R)-2-acetamido-2-acetoxy-3,4,6-tri-O-acetyl-alpha-D-arabino-hexopyrano syl fluoride. 2,4-Dinitrophenyl 2-deoxy-2-fluoro-beta-cellobioside was an inactivator of the exoglucanase from Cellulomonas fimi while 2-deoxy-2-fluoro-alpha-maltosyl and alpha-maltotriosyl fluorides were slow substrates of human pancreatic alpha-amylase and rabbit muscle glycogen debranching enzyme, respectively.}, keywords = {ACETYL HYPOFLUORITE, beta-glucosidase, CATALYTIC FLEXIBILITY, DERIVATIVES, ENZYME, GLYCOSYLASES, hydration, INTERMEDIATE, MECHANISM}, isbn = {0008-6215}, url = {://A1993MD38700007}, author = {McCarter, J. D. and Adam,Michael J. and Braun, C. and Namchuk, M. and Tull, D. and Withers, S. G.} } @article {7230, title = {THE 1992 ALCAN AWARD LECTURE EXCURSIONS AROUND THE PERIODIC-TABLE - LIGAND DESIGN IN INORGANIC-CHEMISTRY}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {70}, number = {12}, year = {1992}, note = {ISI Document Delivery No.: KL565Times Cited: 56Cited Reference Count: 38}, month = {Dec}, pages = {2839-2845}, type = {Article}, abstract = {An overview is given on the strategy used to come up with the design of a new type of ligand that is appropriate for coordination to both the late metals and the early metals. The coordination chemistry of the potentially tridentate ligand -N(SiMe2CH2PR2)2 is developed starting with the Ni triad and then the heavier members of group 9, namely rhodium and iridium. It is with iridium that reactive fragments such as methylene and vinylidene have been stabilized and their chemistry examined. Extension to groups 3, 4, and the lanthanides is also discussed. With these elements, phosphine coordination imparts new reactivity patterns such as alkane elimination with group 3 and dinitrogen activation with group 4. In addition, the side-on binding mode for N2 attached to a dinuclear zirconium system is also presented.}, keywords = {asymmetric synthesis, CARBON BOND FORMATION, DERIVATIVES, DINITROGEN, FLUXIONAL BEHAVIOR, HAFNIUM(IV), hydride, MULTI-DENTATE LIGANDS, PHOSPHINE COMPLEXES, RAY CRYSTAL-STRUCTURE}, isbn = {0008-4042}, url = {://A1992KL56500001}, author = {Fryzuk,Michael D.} } @article {7206, title = {CRYSTAL AND MOLECULAR-STRUCTURE OF AN UNUSUAL UNSYMMETRICAL ISOMER OF 1,2-OS3(CO)10(P(C6H5)[(ETA-C5H4)FE(ETA-C5H5)]2)2}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {70}, number = {9}, year = {1992}, note = {ISI Document Delivery No.: JW978Times Cited: 2Cited Reference Count: 17}, month = {Sep}, pages = {2329-2334}, type = {Article}, abstract = {{The reaction of Os3(CO)10(MeCN)2 with PFc2Ph (Fc = (eta-C5H4)Fe(eta-C5H5)) affords the unsymmetrical isomer of 1,2-Os3(CO)10(PFc2Ph)2, 2. Crystals of 2 are monoclinic}, keywords = {CLUSTERS, DERIVATIVES}, isbn = {0008-4042}, url = {://A1992JW97800002}, author = {Cullen, W. R. and Rettig, S. J. and Zheng, T. C.} } @article {7395, title = {A DIRECT ROUTE TO NIOBIUM(V) AND TANTALUM(V) FLUORIDE FLUOROSULFATES}, journal = {Journal of Fluorine Chemistry}, volume = {58}, number = {1}, year = {1992}, note = {ISI Document Delivery No.: JN447Times Cited: 7Cited Reference Count: 15}, month = {Jul}, pages = {81-85}, type = {Article}, abstract = {A simple one-step synthesis for niobium(V) and tantalum(V) fluoride fluorosulfates is reported. The procedure involves the oxidation of the respective metal by bis(fluorosulfuryl)peroxide, S2O6F2, in the presence of the corresponding metal pentafluoride at room temperature and leads to colorless, viscous liquids. Of the resulting products, those of the general composition MFn(SO3F)5-n (M = Nb, Ta; n greater-than-or-equal-to 3) can be distilled in vacuo without decomposition. As an example, the synthesis of TaF3(SO3F)2 is described in detail.}, keywords = {DERIVATIVES}, isbn = {0022-1139}, url = {://A1992JN44700009}, author = {Zhang, D. L. and Aubke, F.} } @article {7380, title = {SELECTED REACTIONS OF FLUORINE-FLUOROSULFATE, FOSO2F}, journal = {Journal of Fluorine Chemistry}, volume = {59}, number = {3}, year = {1992}, note = {ISI Document Delivery No.: KF321Times Cited: 8Cited Reference Count: 36}, month = {Dec}, pages = {333-349}, type = {Article}, abstract = {The reactions of fluorine-fluorosulfate, FOSO2F, with SSF2, SeF4, AsF3 and MoF5 have been studied, and its previously reported reactions with SF4, Br2 and I2 re-investigated in order to test its suitability as a synthetic reagent. All substrates reacted exothermically, and sometimes explosively, between 80-298 K. The presence of the byproducts obtained may be rationalized by the thermal decomposition of some of the FOSO2F, which proceeds along two pathways, i.e. FOSO2F {\textendash}> 1/2O2 + SO2F2 and FOSO2F {\textendash}> 1/2F2 + 1/2S2O6F2, during the extremely exothermic reactions via radical intermediates. The fluorine formed gives rise to fully fluorinated products, and the SO3F. radicals, initially formed, either dimerize to give S2O6F2 or decompose to O2 and S2O5F2. Element fluoride-fluorosulfates, when formed at all, were obtained in low yields only when SO2F2 or SO2FCl were used as suitable moderators. The complete vibrational spectra of EF5OSO2F (E = S, Se or Te) have been studied and assigned. The reactions of I2, Br2 and AsF3 with FOSO2F yielded viscous liquids of the approximate, non-stoichiometric composition EFn(SO5F)5-n (E = As or I) and EFn(SO3F)3-n (E = Br), with n = non-integral number. All compounds were characterized by their vibrational and F-19 NMR spectra, and in the case of SeF5OSO2F by Se-77 NMR methods.}, keywords = {DERIVATIVES, GOLD(III) FLUOROSULFATE, halogen, ION, SPECTRA, TRIS(FLUOROSULFATE)}, isbn = {0022-1139}, url = {://A1992KF32100004}, author = {Willner, H. and Mistry, F. and Aubke, F.} } @article {7282, title = {STRUCTURAL STUDIES OF ORGANOBORON COMPOUNDS .51. N-METHYLHYDROXYLAMINE(O-B)2,5-DIPHENYL-1,3,2-DIOXABOROLAN-4-ONE}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {70}, number = {4}, year = {1992}, note = {ISI Document Delivery No.: JH895Times Cited: 7Cited Reference Count: 43}, month = {Apr}, pages = {1188-1194}, type = {Article}, abstract = {{Three synthetic methods for the preparation of N-methylhydroxylamine(O-B)2,5-diphenyl-1,3,2-dioxaborolan-4-one (2-(1-oxa-2-azoniapropyl)-2,5-diphenyl-1,3-dioxa-2-boratacyclopentan-4-o ne), 9, in good yield are described. Crystals of this material are triclinic}, keywords = {ACTIVATION, CRYSTAL, DERIVATIVES, HYDROXAMIC ACIDS, HYDROXYLAMINE, MODEL REACTIONS, MONOCYCLIC AROMATIC-AMINES, N-ARYL-O-(ALPHA-AMINOACYL)HYDROXYLAMINES, PHENACETIN, ULTIMATE CARCINOGENS}, isbn = {0008-4042}, url = {://A1992JH89500022}, author = {Kliegel, W. and Schumacher, U. and Rettig, S. J. and Trotter, J.} } @article {7038, title = {HYDRIDO THIOLATO AND THIOLATO COMPLEXES OF RUTHENIUM(II) CARBONYL PHOSPHINES}, journal = {Inorganic Chemistry}, volume = {30}, number = {24}, year = {1991}, note = {ISI Document Delivery No.: GR813Times Cited: 52Cited Reference Count: 76}, month = {Nov}, pages = {4617-4627}, type = {Article}, abstract = {{Oxidative addition of RSH (R = H, alkyl, aryl) or RSSR (R = aryl) to Ru(CO)2L3 (L = PPh3, 1) yields respectively cct-RuH(SR)(CO)2L2 (type 2) (cct = cis,cis,trans) or cct-Ru(SR)2(CO)2L2 (type 3); a hydrido selenolate species is made similarly using PhSeH. Methods for in situ formation of corresponding mixed bis(thiolate) species are also given. 1 is generally unreactive toward thioethers, although with propylene sulfide cct-Ru(eta-2-S2) (CO)2L2 is produced. Metathesis reactions of cct-RuCl2(CO)2L2 with NaSR salts yield 3 (R = aryl) or, when R = Et, cct-RuCl(SEt)(CO)2L2 or [L(CO)2Ru(mu-2-SEt)2(mu-3-SEt)Na(THF)]2 (4), depending on reaction conditions. The complexes are characterized by IR spectroscopy, H-1, P-31, and, in some cases, C-13 NMR spectroscopy, and for 2g and 3g (R = SC6H4pMe) and 4, X-ray crystallography. All three complexes crystallized in the space group P1BAR. For 2g}, keywords = {CHEMISTRY, DERIVATIVES, MECHANISM, METHYLDISULFIDO-LIGAND, MOLECULAR-STRUCTURE, NUCLEAR MAGNETIC-RESONANCE, OSMIUM, REACTIVITY, TRANSITION-METALS, X-RAY CRYSTAL}, isbn = {0020-1669}, url = {://A1991GR81300031}, author = {Jessop, P. G. and Rettig, S. J. and Lee, C. L. and James, Brian R.} } @article {7013, title = {PHOSPHINE COMPLEXES OF THE EARLY METALS AND THE IANTHANOIDS}, journal = {Pure and Applied Chemistry}, volume = {63}, number = {6}, year = {1991}, note = {ISI Document Delivery No.: FN255Times Cited: 21Cited Reference Count: 2314TH INTERNATIONAL CONF ON ORGANOMETALLIC CHEMISTRYAUG 19-24, 1990DETROIT, MIINT UNION PURE \& APPL CHEM, DIV INORGAN CHEM, WAYNE STATE UNIV}, month = {Jun}, pages = {845-850}, type = {Proceedings Paper}, abstract = {The coordination chemistry of the mixed-donor tridentate ligand -N(SiMe2CH2PR2)2 with the early transition metals of groups 3 and 4 and the lanthanide elements will be presented. This ancillary ligand has allowed for the formation of phosphine complexes of these hard elements which has in turn induced new reactivity patterns for hydrocarbyl ligands.}, keywords = {DERIVATIVES, F-BLOCK METALS, FLUXIONAL BEHAVIOR, GROUP-4, HAFNIUM(IV), LIGANDS, RAY CRYSTAL-STRUCTURE, ZIRCONIUM(IV)}, isbn = {0033-4545}, url = {://A1991FN25500008}, author = {Fryzuk,Michael D. and Haddad, T. S. and Berg, D. J. and Rettig, S. J.} } @article {7012, title = {PREPARATION AND ISOMERIZATION OF 1-PHENYLSELENO 1,3-DIENES}, journal = {Journal of Organic Chemistry}, volume = {56}, number = {26}, year = {1991}, note = {ISI Document Delivery No.: GW891Times Cited: 18Cited Reference Count: 33}, month = {Dec}, pages = {7201-7211}, type = {Article}, abstract = {{The preparation of a series of 1-phenylseleno 1,3-dienes is described starting from enyne derivatives via a hydrozirconation/transfer sequence. Hydrozirconation of a series of conjugated enynes having the general formula HC = CCR1 = CR2R3 (3a: R1 = R2 = R3 = H; 3b: R1 = R3 = H}, keywords = {CONVENIENT PREPARATION, DERIVATIVES, DIELS-ALDER REACTIONS, HYDROZIRCONATION, ORGANIC-SYNTHESIS, ORGANOSELENIUM CHEMISTRY, selenium, TRANSITION-METAL DIENYLS, transmetalation, ZIRCONIUM}, isbn = {0022-3263}, url = {://A1991GW89100006}, author = {Fryzuk,Michael D. and Bates, G. S. and Stone, C.} } @article {6997, title = {RHODIUM(I) COMPLEXES OF BETA-DIKETONATES AND RELATED LIGANDS AS HOMOGENEOUS HYDROGENATION CATALYSTS}, journal = {Journal of Molecular Catalysis}, volume = {66}, number = {3}, year = {1991}, note = {ISI Document Delivery No.: FW904Times Cited: 22Cited Reference Count: 32}, month = {Jun}, pages = {251-269}, type = {Article}, abstract = {{Rhodium(I) complexes of beta-diketonates such as bis(eta-2-ethene)[1,3-(1-phenyl)-butanedionato-O,O{\textquoteright}]rhodium(I) and related (O ... O) ligands are active catalysts for the hydrogenation of unhindered alkenes at 30-degrees-C (1 atm H-2). Substrates such as alpha-acylaminocinnamic acid are not hydrogenated under these conditions, a result that can be used as a test for homogeneity in these catalytic systems. The crystal structures of two catalysts are described: bis(eta-2 -ethene)[1,3-(1-ferrocenyl)-butanedionato-O,O{\textquoteright}] rhodium(I), orthorhombic, space group P2(1)2(1)2(1), with a = 7.8550(4)}, keywords = {DERIVATIVES, IRIDIUM(I), OLEFINS}, isbn = {0304-5102}, url = {://A1991FW90400001}, author = {Cullen, W. R. and Rettig, S. J. and Wickenheiser, E. B.} } @article {7015, title = {THERMAL AND PHOTOCHEMICAL-TRANSFORMATIONS OF ORGANOIRIDIUM PHOSPHIDE COMPLEXES - MECHANISTIC STUDIES ON CARBON PHOSPHORUS BOND FORMATION TO GENERATE CYCLOMETALATED HYDRIDE COMPLEXES BY ALPHA-HYDRIDE ABSTRACTION}, journal = {Journal of the American Chemical Society}, volume = {113}, number = {23}, year = {1991}, note = {ISI Document Delivery No.: GP037Times Cited: 28Cited Reference Count: 62}, month = {Nov}, pages = {8724-8736}, type = {Article}, abstract = {{The thermal and photolytic transformations of a series of methyliridium(III) phosphide complexes are described. Complexes of the formula Ir(CH3)PR2[N(SiMe2CH2PPh2)2] (R = Ph, Me) rearrange thermally to generate the corresponding cyclometalated derivatives fac-Ir(eta-2-CH2PR2)H[N(SiMe2CH2PPh2)2]; continued thermolysis results in the formation of the iridium(I) phosphine complexes Ir(PMeR2)[N(SiMe2CH2PPh2)2]. Under photolytic conditions the phosphide derivatives rearrange directly to the phosphine complexes with no observable intermediates. The phenylphosphide complex Ir(CH3)PHPh[N-(SiMe2CH2PPh2)2] rearranges directly to the phosphine derivative Ir(PHPhMe)[N(SiMe2CH2PPh2)2] both thermally and photolytically with no observable intermediates. Crystals of lr(CH3)PPh2[N(SiMe2CH2PPh2)2] are monoclinic with a = 13.506 (3) angstrom}, keywords = {ACTIVATION, C-H, CHEMISTRY, CRYSTAL-STRUCTURE, DERIVATIVES, HYDROGEN-BONDS, IRIDIUM, LIGAND, REACTIVITY, REDUCTIVE ELIMINATION}, isbn = {0002-7863}, url = {://A1991GP03700020}, author = {Fryzuk,Michael D. and Joshi, K. and Chadha, R. K. and Rettig, S. J.} }