@article {2610,
	title = {HL2[P(1,2-O(2)C(6)H4)(3)] (L = DMSO or DMF): A Convenient Proton Source with a Weakly Basic Phosphorus(V) Anion},
	journal = {Organometallics},
	volume = {28},
	number = {15},
	year = {2009},
	note = {ISI Document Delivery No.: 476PYTimes Cited: 0Cited Reference Count: 114Siu, Paul W. Gates, Derek P.},
	month = {Aug},
	pages = {4491-4499},
	type = {Review},
	abstract = {Treating phosphorus pentachloride with catechol (3 equiv) followed by the addition of dimethylsulfoxide (DMSO) or dimethylformamide (DMF) affords isolable bronsted acids of tris- (o-phenylenedioxy)phosphate anion, [p(1,2-O2C6H4)(3)](-). Specifically. H(DMSO)(2)[P(1,2-O2C6H4)(3)] and H(DMF)(2)[P(1,2-O2C6H4)(3)] have been isolated as crystalline solids. The downfield shifts of the acidic proton in their H-1 NMR spectra are consistent with its expected high acidity. The molecular structures of H(DMSO)(2)[P(1,2-O2C6H4)(3)] and H(DMF)(2)[P(1,2-O2C6H4)(3)] reveal that the protons in each are O-bound by either DMSO (x2) or DMF (x2). The N-H stretching frequency for the Oct(3)NH[P(1,2-O2C6H4)(3)] ((V) over bar (N-H) =3129 cm(-1)) is identical to that observed for trioctylammonium tetrafluoroborate ((v) over bar (N-H) = 3129 cm(-1)), suggesting that the basicity of these two weakly coordinating anions is similar. A preliminary investigation of the effectiveness of H(DMF)(2)[p(1,2-O2C6H4] in the protonolysis of metal-alkyl bonds was undertaken. Treating (dppe) pdMe(2) [dppe = 1,2-bis(diphenylphosphino)ethane] with H(DMF)(2)[P(1,2-O2C6H4)(3)] affords either [(dppe)pd(NCMe)Me][P(1,2-O2C6H4)(3) (1:1 ratio) or [(dppe)pd(NCMe)(2)(][P(1,2-O2C6H4)(3)](2) (1:2 ratio), both of which are structurally characterized.},
	keywords = {ALTERNATING COPOLYMERIZATION, ANIONS, CARBON-MONOXIDE, COORDINATING ANIONS, CRYSTAL-STRUCTURE, DIMETHYL-SULFOXIDE, MIGRATORY INSERTION, MOLECULAR-STRUCTURE, OLEFIN, PALLADIUM(II) COMPLEXES, POLYMERIZATION, SUPERWEAK},
	isbn = {0276-7333},
	url = {<Go to ISI>://000268455900036},
	author = {Siu, P. W. and Gates, D. P.}
}
@article {1161,
	title = {Comparison of hyperbranched and linear polyglycidol unimolecular reverse micelles as nanoreactors and nanocapsules},
	journal = {Macromolecular Rapid Communications},
	volume = {26},
	number = {3},
	year = {2005},
	note = {ISI Document Delivery No.: 897MDTimes Cited: 28Cited Reference Count: 20},
	month = {Feb},
	pages = {155-159},
	type = {Article},
	abstract = {Amphiphilic-hyperbranched polyglycidols and a linear analogue were tested for the unimolecular elimination (E1) reactions of tert-alkyl iodides. Their encapsulation properties were also compared. The linear polymer was found to have very good "unimolecular reverse micellar" characteristics as well, even though the results showed the advantages of a hyperbranched nature over a one linear one. Our results showed the need for a direct comparison of branched and linear polymers for any application.},
	keywords = {CATALYSIS, host-guest systems, hyperbranched, LIGHT-SCATTERING, MOLECULAR NANOCAPSULES, POLYGLYCEROLS, polyglycidol, POLYMERIZATION, POLYMERS, unimolecular reverse micelle},
	isbn = {1022-1336},
	url = {<Go to ISI>://000227007400005},
	author = {Kumar, K. R. and Brooks, D. E.}
}
@article {1263,
	title = {Synthesis and reactivity of zirconium and hafnium complexes incorporating chelating diamido-N-heterocyclic-carbene ligands},
	journal = {Journal of Organometallic Chemistry},
	volume = {690},
	number = {24-25},
	year = {2005},
	note = {ISI Document Delivery No.: 994VFTimes Cited: 36Cited Reference Count: 51},
	month = {Dec},
	pages = {5788-5803},
	type = {Article},
	abstract = {Early transition metal complexes employing a diamido N-heterocyclic carbene (NHC) ligand set (denoted [NCN]) render the centrally disposed NHC moiety stable to dissociation. Aminolysis reactions with the mesityl-substituted ligand precursor ((Mes)[NCN]H-2) and M(NMe2)(4) (M = Zr, Hf) provide bis(amido)-NHC-metal complexes that can be further converted to chloro and alkyl derivatives. Activation of (Mes)[NCN]M(CH3)(2) with [Ph3C][B(C6F5)(4)] yields {(Mes)[NCN]MCH3} {B(C6F5)(4)}, which is surprisingly inactive for the polymerization of 1-hexene. The zirconium cation did, however, show moderate ability to catalytically polymerize ethylene. The hafnium dialkyls are thermally stable with the exception of the diethyl complex, (Mes)[NCN]Hf(CH2CH3)(2), which undergoes P-hydrogen transfer and subsequent C-H bond activation with an ortho-methyl substituent on the mesityl group. The hafnium dialkyl complexes also insert carbon monoxide and substituted isocyanides to yield eta(2)-acyls and eta(2)-iminoacyls, respectively. In some circumstances, further C-C bond coupling occurs to yield enediolates and eneamidolate metallocycles. The molecular structures of (Mes)[NCN]Hf(CH2CHMe2)(2), (Mes)[NCN]Hf(eta(2)-(2,6-Me2C6H3NCCH3)(CH3), (Mes)[NCN]Hf(eta(2)-(2,6-Me2C6H3NCCH3)(2), (Mes)[NCN]Hf(OC(CH3)=C(CH3)NXy), and [(Mes)[NCN]Hf(OC(Bu-i)=C(Bu-i)O)](2) are included. (c) 2005 Elsevier B.V. All rights reserved.},
	keywords = {AMIDO, CARBON-MONOXIDE, CHEMISTRY, DONORS, ETA-2-IMINOACYL, hafnium, LIVING POLYMERIZATION, MIGRATORY INSERTION, N-heterocyclic carbene, OLEFIN, POLYMERIZATION, PROPERTIES, SPECTROSCOPIC, STABLE CARBENES, STRUCTURAL-CHARACTERIZATION, tridentate ligand, ZIRCONIUM, ZIRCONOCENE COMPLEXES},
	isbn = {0022-328X},
	url = {<Go to ISI>://000234058600046},
	author = {Spencer, L. P. and Fryzuk,Michael D.}
}
@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 = {<Go to ISI>://000221124300061},
	author = {Liu, X. and Sternberg, E. and Dolphin, D.}
}
@article {517,
	title = {Analysis of X-ray photoelectron spectra of electrochemically prepared polyaniline by DFT calculations using model molecules},
	journal = {Journal of Molecular Structure},
	volume = {608},
	number = {2-3},
	year = {2002},
	note = {ISI Document Delivery No.: 536ABTimes Cited: 1Cited Reference Count: 44},
	month = {May},
	pages = {175-182},
	type = {Article},
	abstract = {In order to clarify the electronic state of polyaniline synthesized electrochemically, we analyzed valence X-ray photoelectron spectra (XPS) and core-electron binding energies of N,N{\textquoteright}-Diphenyl-1,4-phenylenediamine and polyaniline by deMon density-functional theory calculations (DFT) using the molecule and model molecule, respectively. Polyaniline has been synthesized electrochemically from two different thin films on platinum plates in oxidation and reduction states, respectively. Valence XPS of the conductive polymers were analyzed by deMon DFT calculations using model tetramers of the four chemical structural formulae (1S, 2S, 1A, and 2A) which MacDiarmid and co-workers proposed. We can conclude that the oxidized polyanililine corresponds to the 2A type, while the reduction form approximated the 1S type. (C) 2002 Elsevier Science B.V. All rights reserved.},
	keywords = {APPROXIMATION, C1S SPECTRA, CONTAINING, deMon DFT calculations, DENSITY-FUNCTIONAL CALCULATIONS, ELECTRON BINDING-ENERGIES, electronic state, interconversion, OLIGOMERS, polyaniline, POLYMERIZATION, POLYMERS, SPECTROSCOPY, XPS},
	isbn = {0022-2860},
	url = {<Go to ISI>://000174677600008},
	author = {Takaoka, K. and Otsuka, T. and Naka, K. and Niwa, A. and Suzuki, T. and Bureau, C. and Maeda, S. and Hyodo, K. and Endo, K. and Chong, D. P.}
}
@article {405,
	title = {Synthesis and characterization of polymer brushes of poly(N,N-dimethylacrylamide) from polystyrene-latex by aqueous atom transfer radical polymerization},
	journal = {Macromolecules},
	volume = {35},
	number = {11},
	year = {2002},
	note = {ISI Document Delivery No.: 554GUTimes Cited: 64Cited Reference Count: 51},
	month = {May},
	pages = {4247-4257},
	type = {Article},
	abstract = {Negatively charged polystyrene latex was synthesized, and a copolymer shell of 2-(methyl-2{\textquoteright}-chloropropionato)ethyl acrylate (HEA-Cl) and styrene was added, from which poly(N,N-dimethylacrylamide) (PDMA) was polymerized by atom transfer radical polymerization in aqueous suspension at room temperature. Increasing monomer concentration in the presence of CuCl or CuBr and one of three ligands (N,N,N{\textquoteright},N{\textquoteright},N"-pentamethyldiethylenetriamine (PMDETA), 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA), and tris [2-(dimethylamino)ethyl] amine (Me6TREN)) produced grafts whose molecular weight increased to over 600 000 and polydispersities in the range of 1.3-1.8, determined from chains recovered following cleavage by base. Hydrodynamic brush thicknesses were 70-800 nm, and average chain separations, calculated from M-n and the mass of polymer recovered per particle, varied from 4.0 to 1.1 nm. Very high grafting densities were achieved with good molecular weight control, the highest densities yet reported for high molecular weight polymer chains grown from a surface. Control of the polymerization was improved by addition of Cu(II) to enhance deactivation of free radicals, by including a low concentration of exogenous hydrophobic initiator at high monomer concentration and by reducing latex concentration. Increasing the concentration of exogenous initiator reduced graft thickness but eliminated control over the polydispersity. The unusual conditions required for optimization of the reaction and the observation of decreasing chain separation as M-n increased were explained by invoking a model of the particle surface that took into account the finite depth and high copolymer concentration of the region in which chains were initiated and particularly the fixed charges due to the sulfate initiator of shell copolymerization.},
	keywords = {(METH)ACRYLAMIDES, ADSORPTION, AMBIENT-TEMPERATURE, BLOCK-COPOLYMERS, CARBOCATIONIC, FACILE, POLYELECTROLYTE BRUSHES, POLYMERIZATION, SELF-ASSEMBLED MONOLAYERS, SURFACE, SYNTHESIS, TETHERED CHAINS},
	isbn = {0024-9297},
	url = {<Go to ISI>://000175728100006},
	author = {Jayachandran, K. N. and Takacs-Cox, A. and Brooks, D. E.}
}
@article {5076,
	title = {Reaction of [P2N2]Ta=CH2(Me) with ethylene: Synthesis of [P2N2]Ta(C2H4)Et, a neutral species with a beta-agostic ethyl group in equilibrium with an alpha-agostic ethyl group ([P2N2] = PhP(CH2SiMe2NSiMe2CH2)(2)PPh)},
	journal = {Journal of the American Chemical Society},
	volume = {123},
	number = {8},
	year = {2001},
	note = {ISI Document Delivery No.: 405LXTimes Cited: 26Cited Reference Count: 65},
	month = {Feb},
	pages = {1602-1612},
	type = {Article},
	abstract = {The photolysis of [P2N2]TaMe3 ([P2N2] = PhP(CH2SiMe2NSiMe2CH2)(2)PPh) produces [P2N2]Ta=CH2(Me) as the major product. The thermally unstable methylidene complex decomposes in solution in the absence of trapping agents to unidentified products. However, in the presence of ethylene [P2N2]Ta=CH2(Me) is slowly converted to [P2N2]Ta(C2H4)Et, with [P2N2]Ta(C2H4)Me observed as a minor product. A mechanistic study suggests that the formation of [P2N2]Ta(C2H4)Et results from the trapping of [P2N2]TaEt, formed by the migratory insertion of the methylene moiety into the tantalum-methyl bond. The minor product, [P2N2]Ta(C2H4)Me, forms from the decomposition of a tantalacyclobutane resulting from the addition of ethylene to [P2N2]Ta=CH2(Me) and is accompanied by the production of an equivalent of propylene. Pure [P2N2]Ta(C2H4)Et can be synthesized by hydrogenation of [P2N2]TaMe3 in the presence of PMe3, followed by the reaction bf ethylene with the resulting trihydride. Crystallographic and NMR data indicate the presence of a beta -agostic interaction between the ethyl group and tantalum center in [P2N2]Ta(C2H4)Et. Partially deuterated analogues of [P2N2]Ta(C2H4)Et show a large isotopic perturbation of resonance for both the beta -protons and the alpha -protons of the ethyl group, indicative of an equilibrium between a beta -agostic and an a-agostic interaction for the ethyl group in solution. An EXSY spectrum demonstrates that an additional fluxional process occurs that exchanges all of the H-1 environments of the ethyl and ethylene ligands. The mechanism of this exchange is believed to involve the direct transfer of the beta -agostic hydrogen atom from the ethyl group to the ethylene ligand, via the so-called beta -hydrogen transfer process.},
	keywords = {ALKYL ALKENE, C-H, CHAIN PROPAGATION, COMPLEXES, METAL-CARBON BONDS, MIGRATORY INSERTION, MOLECULAR-STRUCTURES, NUCLEAR-MAGNETIC-RESONANCE, OLEFIN, POLYMERIZATION, RAY CRYSTAL-STRUCTURE, TRANSITION-METALS},
	isbn = {0002-7863},
	url = {<Go to ISI>://000167162100008},
	author = {Fryzuk,Michael D. and Johnson, S. A. and Rettig, S. J.}
}
@article {4548,
	title = {One-electron oxidation of paramagnetic chromium(II) alkyl complexes with alkyl halides: synthesis and structure of five-coordinate chromium(III) complexes},
	journal = {Journal of the Chemical Society-Dalton Transactions},
	number = {2},
	year = {1999},
	note = {ISI Document Delivery No.: 162JPTimes Cited: 18Cited Reference Count: 69},
	month = {Jan},
	pages = {147-154},
	type = {Article},
	abstract = {The reaction of square-planar, high-spin CrR[N(SiMe2CH2PPh2)(2)] (R = Me, CH2SiMe3) with alkyl halides (MeI, CF3CH2I, MeBr, PhCH2Cl) generates one-electron oxidation products Cr(R)X[N(SiMe2CH2PPh2)(2)], unusual examples of five-coordinate chromium(III) complexes. Cr(Me)Br[N(SiMe2CH2PPh2)(2)] and Cr(CH2SiMe3)Cl[N(SiMe2CH2PPh2)(2)] have structurally characterized. Alkylation of the latter complex with LiCH2SiMe3 gave a five-coordinate Cr(III) dialkyl complex Cr(CH2SiMe3)(2)[N(SiMe2CH2PPh2)(2)](2), which was structurally characterized as well. Attempts to isolate sterically unencumbered Cr(III) dialkyl (e.g., dimethyl) complexes resulted in decomposition. Addition of an excess of PhCH2Cl to {[(Ph2PCH2SiMe2)(2)N]Cr}(2)(mu-Cl)(2) resulted in halide-transfer to form CrCl2(TNF)[N(SiMe2CH2PPh2)(2)] in low yield. Reaction of the low-spin CrCp[N(SiMe2CH2PPh2)(2)] complex with PhCH2Cl, however, gave both Cr(Cp)(CH2Ph)[N(SiMe2CH2PPh2)(2)] and Cr(CP)Cl[N(SiMe2CH2CH2PPh2)(2)]. The five five-coordinate Cr(III) alkyl halide complexes do not polymerize ethylene at 60 degrees C and 1 atm; the dialkyl complex Cr(CH2SiMe3)(2)[N(SiMe2CH2PPh2)(2)] does catalyze polyethylene formation but is quickly deactivated. A discussion comparing the structural distortions observed in these five-coordinate high-spin d(3) Cr(III) complexes with those observed in the analogous low-spin d(6) Ir(III) complexes is presented.},
	keywords = {17-ELECTRON, 5-COORDINATE, ATOM TRANSFER-REACTIONS, CHEMISTRY, CRYSTAL-STRUCTURE, D6 ML5 COMPLEXES, NMR-SPECTROSCOPY, ORGANIC HALIDES, POLYMERIZATION, REACTIVITY},
	isbn = {0300-9246},
	url = {<Go to ISI>://000078342700010},
	author = {Fryzuk,Michael D. and Leznoff, D. B. and Rettig, S. J. and Young, V. G.}
}
@article {4570,
	title = {Poly(styrene) latex carrying cerium(IV)-initiated terminally attached cleavable chains: Analysis of grafted chains and model of the surface layer},
	journal = {Macromolecules},
	volume = {32},
	number = {3},
	year = {1999},
	note = {ISI Document Delivery No.: 166HKTimes Cited: 14Cited Reference Count: 40},
	month = {Feb},
	pages = {565-573},
	type = {Article},
	abstract = {Ce(IV)-initiated grafting of N(2-methoxyethyl-acrylamide) (MEA) to a shell of poly(styrene-co-2-hydroxyethyl acrylate) on polystyrene latex has been performed and the molecular weight distribution of the graft determined by size exclusion chromatography (SEC) on grafted chains cleaved from the surface. Cationic poly(styrene) beads were covered with a shell containing poly(styrene-co-2-hydroxyethyl acrylate) utilizing an azo initiator. The density of the surface hydroxyl groups was assessed by saponification of the ester bonds followed by conductometric titration of the resulting carboxylic residues. Ce(TV) redox initiation of MEA from the surface hydroxyl groups produced chains terminally attached to the latex surface. MEA consumption kinetics were monitored by HPLC of the supernatant on a reverse phase column. Competing solution polymerization of MEA occurred, probably due to leakage of shell copolymer from the beads. The terminally attached chains were characterized by quantitative SEC following cleavage from the surface by saponification, allowing a model of the tethered surface to be developed.},
	keywords = {ACRYLATE, CARBOXY METHYL CELLULOSE, CHROMATOGRAPHY, COPOLYMERIZATION, METHACRYLATE, POLYMERIZATION, REDOX SYSTEM, STARCH},
	isbn = {0024-9297},
	url = {<Go to ISI>://000078570000005},
	author = {Hritcu, D. and Muller, W. and Brooks, D. E.}
}
@article {4327,
	title = {An investigation of the yang photocyclization reaction in the solid state: Asymmetric induction studies and crystal structure-reactivity relationships},
	journal = {Journal of the American Chemical Society},
	volume = {120},
	number = {49},
	year = {1998},
	note = {ISI Document Delivery No.: 149MWTimes Cited: 101Cited Reference Count: 61},
	month = {Dec},
	pages = {12755-12769},
	type = {Article},
	abstract = {The Norrish/Yang type II photochemistry of 16 ketones having the basic cis-4-tert-butyl-1-benzoylcyclohexane or 2-benzoyladamantane structure has been investigated in the solid state and solution. In both media, ketones bearing methyl substituents alpha to the benzoyl group undergo stereoselective Yang photocyclization to afford endo-arylcyclobutanols. Quantum yield and quenching studies in solution show that the reactions are efficient triplet-mediated processes. Asymmetric induction studies were carried out by providing the reactants with carboxylic acid substituents to which "ionic chiral auxiliaries" were attached through salt formation with optically active amines. Irradiation of the salts (17 in total) in solution gave racemic cyclobutanols, but in the crystalline state, moderate to near-quantitative enantiomeric excesses were obtained. Single crystal X-ray diffraction studies were successfully performed on 10 neutral ketones and four salts. This allowed the reactive gamma-hydrogen atoms to be identified and the distance and angular parameters associated with their abstraction to be tabulated. For the 14 compounds whose crystal structures were determined, the average value of d, the C=O ... H abstraction distance, was 2.61 +/- 0.07 Angstrom, and the values of omega (the gamma-hydrogen out-of-plane angle), Delta (the C=O ... H, angle) and a (the C-H-gamma... O angle) were 53 +/- 11, 84 +/- 7, and 115 +/- 2 degrees, respectively. In a similar manner, the geometric parameters associated with the ring closure reactions of the intermediate 1,4-hydroxy biradicals were estimated from the crystallographic data. This indicates that the biradicals are 66.5 +/- 9.8 and 32.7 +/- 3.2 degrees out of alignment for cleavage, but that they are well oriented for cyclization, with radical separations (D) of 3.08 +/- 0.09 Angstrom. For one of the salts in the adamantane series, the solid-state photoreaction was shown to be topotactic; that is, a single crystal of the reactant salt was transformed quantitatively into a single crystal of the corresponding cyclobutanol salt. Since the absolute configuration of the ionic chiral auxiliary in this case was known, this permitted the absolute steric course of the reaction to be mapped by X-ray crystallography and the abstracted gamma-hydrogen to be identified unequivocally. In addition, the crystal structure of a partially reacted crystal containing 60\% product and 40\% reactant was successfully determined. This showed that the two compounds in the mixed crystal have nearly identical shapes and orientations, thus accounting for the single crystal nature of the process. Finally, it was found that ketones lacking methyl substituents alpha to the benzoyl group an either photochemically unreactive or undergo Norrish type II cleavage. Possible reasons for this difference in behavior are presented and discussed.},
	keywords = {BIRADICALS, CHEMISTRY, CONFORMATIONAL MEMORY, HYDROGEN-ATOM TRANSFERS, II PHOTOPROCESSES, KETONES, ORGANIC-PHOTOCHEMISTRY, PHENYL, POLYMERIZATION, SINGLE-CRYSTAL, TRANSITION STRUCTURES, TRIPLET},
	isbn = {0002-7863},
	url = {<Go to ISI>://000077610100007},
	author = {Leibovitch, M. and Olovsson, G. and Scheffer, J. R. and Trotter, J.}
}
@article {4327,
	title = {An investigation of the yang photocyclization reaction in the solid state: Asymmetric induction studies and crystal structure-reactivity relationships},
	journal = {Journal of the American Chemical Society},
	volume = {120},
	number = {49},
	year = {1998},
	note = {ISI Document Delivery No.: 149MWTimes Cited: 101Cited Reference Count: 61},
	month = {Dec},
	pages = {12755-12769},
	type = {Article},
	abstract = {The Norrish/Yang type II photochemistry of 16 ketones having the basic cis-4-tert-butyl-1-benzoylcyclohexane or 2-benzoyladamantane structure has been investigated in the solid state and solution. In both media, ketones bearing methyl substituents alpha to the benzoyl group undergo stereoselective Yang photocyclization to afford endo-arylcyclobutanols. Quantum yield and quenching studies in solution show that the reactions are efficient triplet-mediated processes. Asymmetric induction studies were carried out by providing the reactants with carboxylic acid substituents to which "ionic chiral auxiliaries" were attached through salt formation with optically active amines. Irradiation of the salts (17 in total) in solution gave racemic cyclobutanols, but in the crystalline state, moderate to near-quantitative enantiomeric excesses were obtained. Single crystal X-ray diffraction studies were successfully performed on 10 neutral ketones and four salts. This allowed the reactive gamma-hydrogen atoms to be identified and the distance and angular parameters associated with their abstraction to be tabulated. For the 14 compounds whose crystal structures were determined, the average value of d, the C=O ... H abstraction distance, was 2.61 +/- 0.07 Angstrom, and the values of omega (the gamma-hydrogen out-of-plane angle), Delta (the C=O ... H, angle) and a (the C-H-gamma... O angle) were 53 +/- 11, 84 +/- 7, and 115 +/- 2 degrees, respectively. In a similar manner, the geometric parameters associated with the ring closure reactions of the intermediate 1,4-hydroxy biradicals were estimated from the crystallographic data. This indicates that the biradicals are 66.5 +/- 9.8 and 32.7 +/- 3.2 degrees out of alignment for cleavage, but that they are well oriented for cyclization, with radical separations (D) of 3.08 +/- 0.09 Angstrom. For one of the salts in the adamantane series, the solid-state photoreaction was shown to be topotactic; that is, a single crystal of the reactant salt was transformed quantitatively into a single crystal of the corresponding cyclobutanol salt. Since the absolute configuration of the ionic chiral auxiliary in this case was known, this permitted the absolute steric course of the reaction to be mapped by X-ray crystallography and the abstracted gamma-hydrogen to be identified unequivocally. In addition, the crystal structure of a partially reacted crystal containing 60\% product and 40\% reactant was successfully determined. This showed that the two compounds in the mixed crystal have nearly identical shapes and orientations, thus accounting for the single crystal nature of the process. Finally, it was found that ketones lacking methyl substituents alpha to the benzoyl group an either photochemically unreactive or undergo Norrish type II cleavage. Possible reasons for this difference in behavior are presented and discussed.},
	keywords = {BIRADICALS, CHEMISTRY, CONFORMATIONAL MEMORY, HYDROGEN-ATOM TRANSFERS, II PHOTOPROCESSES, KETONES, ORGANIC-PHOTOCHEMISTRY, PHENYL, POLYMERIZATION, SINGLE-CRYSTAL, TRANSITION STRUCTURES, TRIPLET},
	isbn = {0002-7863},
	url = {<Go to ISI>://000077610100007},
	author = {Leibovitch, M. and Olovsson, G. and Scheffer, J. R. and Trotter, J.}
}
@article {3332,
	title = {QUANTITATIVE KINETIC-ANALYSIS BY HIGH-RESOLUTION SI-29 NMR-SPECTROSCOPY OF THE INITIAL-STAGES IN THE SOL-GEL FORMATION OF SILICA-GEL FROM TETRAETHOXYSILANE},
	journal = {Chemistry of Materials},
	volume = {7},
	number = {10},
	year = {1995},
	note = {ISI Document Delivery No.: TB561Times Cited: 38Cited Reference Count: 24},
	month = {Oct},
	pages = {1800-1806},
	type = {Article},
	abstract = {Silicon-29 NMR spectroscopy has been used to determine concentration time dependences of the intermediate species formed in the hydrolysis and first condensation steps in the sol-gel formation of silica gel from tetraethoxysilane. A detailed kinetic analysis of these data yields the rate constants k(1) to k(4) for the hydrolysis reactions and k(5) for the first condensation reaction. It is necessary for the fitting process to consider the last hydrolysis step as an equilibrium process, yielding k(4f) and k(4b) For the first time, from measurements made at different pH values, catalyst independent rate constants have been obtained. For the hydrolysis and condensation reactions, these follow the general trend k(1) < k(2) < k(3) > k(5) with the associated errors reflecting the concentrations of the intermediate species.},
	keywords = {CONDENSATION-REACTIONS, HYDROLYSIS, POLYMERIZATION, TEOS},
	isbn = {0897-4756},
	url = {<Go to ISI>://A1995TB56100009},
	author = {Fyfe, C. A. and Aroca, P. P.}
}
@article {7358,
	title = {MONOMER AND EXCIMER FLUORESCENCE OF HORSE PLASMA GELSOLIN LABELED WITH N-(1-PYRENYL)IODOACETAMIDE},
	journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire},
	volume = {70},
	number = {7},
	year = {1992},
	note = {ISI Document Delivery No.: JP667Times Cited: 3Cited Reference Count: 27},
	month = {Jul},
	pages = {573-578},
	type = {Article},
	abstract = {Horse plasma gelsolin was labelled with the sulfhydryl-specific fluorescent reagent N-(1-pyrenyl)iodoacetamide. The level of incorporation of probe was 1.6 +/- 0.3 mol pyrene/mol gelsolin. The circular dichroism spectrum of pyrenyl-gelsolin and its ability to interact with muscle actin were not different from that found for unmodified gelsolin. The emission from pyrenyl-gelsolin was dominated by a broad emission band centred near 483 nm, characteristic of the presence of pyrene excimers. Analysis of excitation spectra for the monomer and excimer-type fluorescence suggested that ground-state interactions may occur between adjacent pyrenes in the gelsolin structure. In the case either of excimer formation or of ground-state pyrene-pyrene interactions in doubly labelled gelsolin molecules, the modified Cys residues must be in close proximity in the folded protein structure. Thermal denaturation of gelsolin could be monitored by observing the decrease in excimer emission that accompanied heating and unfolding of the tertiary structure. While heat treatment alone did not eliminate excimer fluorescence, digestion of gelsolin with chymotrypsin completely abolished such emission. Also, pyrenyl-gelsolin prepared and studied in 6 M guanidine-HCl exhibited fluorescence characteristic of pyrene monomers exclusively.},
	keywords = {ACTIN-FILAMENTS, BINDING, CIRCULAR-DICHROISM, denaturation, FLUORESCENCE LIFETIME, gelsolin, POLYMERIZATION, PROBE, PROTEIN, PYRENE EXCIMER FLUORESCENCE, PYRENE-ACTIN, STATE, thermal, TROPOMYOSIN},
	isbn = {0829-8211},
	url = {<Go to ISI>://A1992JP66700008},
	author = {Silva, B. E. R. and Koepf, E. K. and Burtnick, L. D. and Turro, N. J.}
}
@article {7352,
	title = {STABILIZATION OF THE STRUCTURE OF HORSE PLASMA VITAMIN-D BINDING-PROTEIN BY DISULFIDE BONDS},
	journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire},
	volume = {70},
	number = {1},
	year = {1992},
	note = {ISI Document Delivery No.: HG742Times Cited: 1Cited Reference Count: 27},
	month = {Jan},
	pages = {10-15},
	type = {Article},
	abstract = {Vitamin D binding protein (DBP) was isolated from horse plasma in a four-step procedure that involved Affi-Gel Blue affinity chromatography, gel filtration, hydroxylapatite chromatography, and anion exchange high-pressure liquid chromatography. The yield of DBP from 80 mL of plasma was 6-7 mg. Horse plasma DBP closely resembles other plasma DBPs, being a tryptophan-free protein of M(r) 53 000. It is able to bind to and block the polymerization of monomeric actin. The secondary structure of DBP was calculated from circular dichroism measurements to be 39\% alpha-helix, 42\% beta-sheet, and 19\% random coil. Circular dichroism and fluorescence studies revealed that the disulfide bonds of DBP contribute substantial structural stabilization to the molecule with respect to thermal denaturation. The thermal stability of DBP can be used to advantage. Incorporation of a brief treatment at 70-degrees-C into the preparative scheme enables omission of one chromatographic step, without detectable alteration of the purified product.},
	keywords = {actin, circular dichroism, CIRCULAR-DICHROISM, COMPLEX, denaturation, DISULFIDE BONDS, FLUORESCENCE, GC-GLOBULIN, POLYMERIZATION, RAT, SERUM, thermal, TROPOMYOSIN, VITAMIN-D BINDING PROTEIN},
	isbn = {0829-8211},
	url = {<Go to ISI>://A1992HG74200002},
	author = {Robinson, R. C. and Burtnick, L. D.}
}
@article {7020,
	title = {REACTIONS OF SILANES WITH THE BINUCLEAR HYDRIDE [(PR(I)2PCH2CH2PPR(I)2)RH]2(MU-H)2 - CATALYTIC DEUTERIUM-EXCHANGE ON DIPHENYLSILANE AND X-RAY STRUCTURE OF [(PR(I)2PCH2CH2PPR(I)2)RH]2(MU-H)(MU-ETA-2-HSIPH2)},
	journal = {Organometallics},
	volume = {10},
	number = {8},
	year = {1991},
	note = {ISI Document Delivery No.: GA275Times Cited: 45Cited Reference Count: 25},
	month = {Aug},
	pages = {2537-2539},
	type = {Note},
	abstract = {Stoichiometric reactions of diphenylsilane (H2SiPh2) with [(dippe)Rh]2(mu-H)2 (1; dippe = 1,2-bis(diisopropylphosphino)ethane) have produced the new compounds [(dippe)Rh]2(mu-H)(mu-eta-2-HSiPh2) (2) and [(dippe)-Rh]2(mu-SiPh2)2 (3). An X-ray structure determination of 2 indicates the presence of a three-center, two-electron Rh-Si-H interaction. Deuterium exchange and silicon-silicon coupling to give 1,1,2,2-tetraphenyldisilane are both observed for diphenylsilane in the presence of catalytic amounts of 1; the isolated silyl-dihydride complex 2 and the bis(silylene) derivative 3 are likely to be active in these catalytic cycles.},
	keywords = {BONDS, CRYSTAL, HYDROSILATION, MOLECULAR-STRUCTURE, MU-SILYLENE COMPLEXES, POLYMERIZATION, PRIMARY ORGANOSILANES, SI, SILICON},
	isbn = {0276-7333},
	url = {<Go to ISI>://A1991GA27500005},
	author = {Fryzuk,Michael D. and Rosenberg, L. and Rettig, S. J.}
}
