@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 {1296, title = {Dynamic C-13 NMR studies of ligand exchange in linear (d(10)) silver(I) and gold(I) and square-planar (d(8)) rhodium(I) homoleptic metal carbonyl cations in superacidic media}, journal = {Magnetic Resonance in Chemistry}, volume = {43}, number = {7}, year = {2005}, note = {ISI Document Delivery No.: 936FUTimes Cited: 0Cited Reference Count: 21}, month = {Jul}, pages = {520-527}, type = {Article}, abstract = {The dynamic CO exchange of the monovalent metal carbonyl cations [Ag((CO)-C-13)](+), [Au((CO)-C-13)(2)](+)-Au((CO)-C-13) SO3F and [Rh((CO)-C-12)(4-x)((CO)-C-13)(x)](+) (x <= 1) in superacidic solutions was studied by variable-temperature C-13 NMR methods. The exchange rates are strongly dependent on the acidity of the solvent, the concentration of metal carbonyl cations and temperature. Whereas a suitable exchange rate of the Ag(I) system is only accessible in magic acid (HSO3F-SbF5), the more stable Au(I) and Rh(I) systems were studied in the less acidic fluorosulfuric acid. Selected solutions of Ag(I), Rh(I) and Au(I) yielded activation barriers Delta G* of 42.7, 43.5, and 56.2 kJ mol(-1) respectively. Copyright (c) 2005 John Wiley \& Sons, Ltd.}, keywords = {C-13 NMR, CO exchange, CRYSTAL, dynamic NMR, fluorosulfuric acid, GOLD, HINDERED INTERNAL ROTATION, HSO3F-SBF5, magic acid, metal carbonyl cations, NMR, NUCLEAR-MAGNETIC-RESONANCE, rhodium, silver, UNDECAFLUORODIANTIMONATE(V), VIBRATIONAL-SPECTRA}, isbn = {0749-1581}, url = {://000229841700003}, author = {von Ahsen, B. and Bach, C. and Balzer, G. and Bley, B. and Bodenbinder, M. and Hagele, G. and Willner, H. and Aubke, F.} } @article {382, title = {Combined solid state NMR and X-ray diffraction investigation of the local structure of the five-coordinate silicon in fluoride-containing as-synthesized STF zeolite}, journal = {Journal of the American Chemical Society}, volume = {124}, number = {26}, year = {2002}, note = {ISI Document Delivery No.: 567YYTimes Cited: 41Cited Reference Count: 48}, month = {Jul}, pages = {7770-7778}, type = {Article}, abstract = {The local structure of the [SiO4/2F](-) unit in fluoride-containing as-synthesized STF zeolite has been experimentally determined by a combination of solid-state NMR and microcrystal X-ray diffraction to be very close to trigonal bipyramidal. Because the fluoride ions are disordered over two sites, the resulting local structure of the [SiO4/2F](-) unit from a conventional XRD refinement is an average between tetrahedral SiO4/2 and five-coordinate [SiO4/2F](-), giving an apparent F-Si distance longer than expected. The correct F-Si distance was determined by slow spinning MAS and fast spinning F-19/Si-29 CP and REDOR solid-state NMR experiments and found to be between 1.72 and 1.79 Angstrom. In light of this, the X-ray structure was re-refined, including the disorder at Si3. The resulting local structure of the [SiO4/2F]- unit was very close to trigonal bipyramidal with a F-Si distance of 1.744 (6) Angstrom, in agreement with the NMR results and the prediction of Density Functional Theory calculations. In addition, further evidence for the existence of a covalent F-Si bond is provided by a F-19{\textendash}>Si-29 refocused INEPT experiment. The resonance for the five-coordinate species at -147.5 ppm in the Si-29 Spectrum is a doublet due to the F-19/Si-29 J-coupling of 165 Hz. The peaks in this doublet have remarkably different effective chemical shift anisotropies due to the interplay of the CSA, dipolar coupling, and J-coupling tensors. The distortions from tetrahedral geometry of the neighboring silicon atoms to the five-coordinate Si3 atom are manifested in increased delta(aniso) values. This information, along with F-Si distances measured by F-19{\textendash}>Si-29 CP experiments, makes it possible to assign half of the Si-29 resonances to unique tetrahedral sites. As well as determining the local geometry of the [SiO4/2F](-) unit, the work presented here demonstrates the complementarity of the solid-state NMR and X-ray diffraction techniques and the advantages of using them together.}, keywords = {5-COORDINATE SILICON, C-13 NMR, CONTAINING OCTADECASIL, CROSS-POLARIZATION, DISTANCE DETERMINATIONS, LOCATION, MOLECULAR-SIEVES, P-31 NMR, POLARIZATION TRANSFER, PROTON-ENHANCED NMR}, isbn = {0002-7863}, url = {://000176516400032}, author = {Fyfe, C. A. and Brouwer, D. H. and Lewis, A. R. and Villaescusa, L. A. and Morris, R. E.} } @article {3452, title = {STRUCTURAL STUDIES ON DIMETHYLTIN(IV) CARBOXYLATES}, journal = {Zeitschrift Fur Anorganische Und Allgemeine Chemie}, volume = {621}, number = {11}, year = {1995}, note = {ISI Document Delivery No.: TC950Times Cited: 6Cited Reference Count: 23}, month = {Nov}, pages = {1875-1882}, type = {Article}, abstract = {{In order to correlate Sn-119 Mossbauer parameters and structural data for dimethyltin(IV) derivatives, the molecular structures of bis(acetato)dimethyltin(IV) and bis(trifluoroace tato)dimethyltin(IV) were determined by single crystal X-ray diffration. Crystals of Me(2)Sn(OOCCH3)(2) are monoclinic}, keywords = {ACIDS, BIS(ACETATO)DIMETHYLTIN(IV), BIS(TRIFLUOROACETATO)DIMETHYLTIN(IV), C-13 NMR, crystal structure, ME2SN(OAC)2, SALTS, X-RAY}, isbn = {0044-2313}, url = {://A1995TC95000008}, author = {Mistry, F. and Rettig, S. J. and Trotter, J. and Aubke, F.} } @article {3452, title = {STRUCTURAL STUDIES ON DIMETHYLTIN(IV) CARBOXYLATES}, journal = {Zeitschrift Fur Anorganische Und Allgemeine Chemie}, volume = {621}, number = {11}, year = {1995}, note = {ISI Document Delivery No.: TC950Times Cited: 6Cited Reference Count: 23}, month = {Nov}, pages = {1875-1882}, type = {Article}, abstract = {{In order to correlate Sn-119 Mossbauer parameters and structural data for dimethyltin(IV) derivatives, the molecular structures of bis(acetato)dimethyltin(IV) and bis(trifluoroace tato)dimethyltin(IV) were determined by single crystal X-ray diffration. Crystals of Me(2)Sn(OOCCH3)(2) are monoclinic}, keywords = {ACIDS, BIS(ACETATO)DIMETHYLTIN(IV), BIS(TRIFLUOROACETATO)DIMETHYLTIN(IV), C-13 NMR, crystal structure, ME2SN(OAC)2, SALTS, X-RAY}, isbn = {0044-2313}, url = {://A1995TC95000008}, author = {Mistry, F. and Rettig, S. J. and Trotter, J. and Aubke, F.} } @article {3029, title = {MICROMORPHOLOGICAL AND C-13 NMR CHARACTERIZATION OF A HUMIC, LIGNIC, AND HISTIC FOLISOL FROM BRITISH-COLUMBIA}, journal = {Canadian Journal of Soil Science}, volume = {74}, number = {1}, year = {1994}, note = {ISI Document Delivery No.: NG042Times Cited: 9Cited Reference Count: 39}, month = {Feb}, pages = {1-15}, type = {Article}, abstract = {The thick folic (mainly upland forest) materials (> 40 cm of accumulated organic material) that occur in the Coastal Western Hemlock Biogeoclimatic Zone in British Columbia have not been described with regard to the spatial interrelationships of the soil constituents in context with the chemical composition of the different horizons. Micromorphological assessment and solid-state C-13 NMR were used to characterize the accumulated folic materials from a Lignic Folisol (northern Vancouver Island), Histic Folisol (Prince Rupert, BC) and a Humic Folisol (Queen Charlotte Islands, BC). Micromorphology provided information on the spatial relationships of the soil constituents and C-13 NMR provided data on the chemical components of the folic materials. Soil faunal activity, primarily from mites, was the dominant soil-forming process observed in the organic horizons of the Folisols, being especially prominent in the Lignic Folisol with the breakdown of woody materials. Solid state C-13 CPMAS NMR spectra facilitated distinguishing three main types of horizons: (1) Horizons derived from accumulated residues (L, Fr, and Hr) showing higher carbohydrate-like C and O-alkyl C values and lower total aromatics; (2) Horizons with advanced decomposition (Hr2, Oh1, and Hd) which were higher in alkyl C; and (3) Horizons derived from ligneous material (Fw and Hdw) where carbohydrate-like C was less than total aromatic C. Implications for adequate nutrient content and forest growth were inferred from the observed micromorphology and chemical composition of the folic materials.}, keywords = {C-13 NMR, CHEMICAL-COMPOSITION, DECOMPOSITION, FAUNAL ACTIVITY, FOLISOL, FOREST SOILS, IONIZATION MASS-SPECTROMETRY, IR, LITTER, MICROMORPHOLOGY, NITROGEN, NUCLEAR-MAGNETIC-RESONANCE, ORGANIC-MATTER, SPECTROSCOPY}, isbn = {0008-4271}, url = {://A1994NG04200001}, author = {Fox, C. A. and Preston, C. M. and Fyfe, C. A.} } @article {7021, title = {ONE-DIMENSIONAL AND 2-DIMENSIONAL HIGH-RESOLUTION SOLID-STATE NMR-STUDIES OF ZEOLITE LATTICE STRUCTURES}, journal = {Chemical Reviews}, volume = {91}, number = {7}, year = {1991}, note = {ISI Document Delivery No.: GP764Times Cited: 106Cited Reference Count: 90}, month = {Nov}, pages = {1525-1543}, type = {Review}, keywords = {C-13 NMR, CRYSTAL-STRUCTURE, CRYSTALLOGRAPHICALLY INEQUIVALENT SITES, HIGH-SILICA ZEOLITE, MAS-NMR, NUCLEAR MAGNETIC-RESONANCE, NUCLEI, ORTHORHOMBIC FRAMEWORK, QUADRUPOLAR, Si-29 NMR, X-RAY-DIFFRACTION}, isbn = {0009-2665}, url = {://A1991GP76400014}, author = {Fyfe, C. A. and Feng, Y. and Grondey, H. and Kokotailo, G. T. and Gies, H.} }