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Representative Series (representative + series)
Selected AbstractsSemi-empirical studies of substituent effects on the ionization of bicyclooctane carboxylic acids and quinuclidinesJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 2 2003Helena Diez y Riega Abstract Semiempirical AM1 calculations were performed for a representative series of 4-substituted bicyclooctane carboxylic acids and quinuclidines. It was found that the Hammett constant, ,I, and the Swain and Lupton field constant, F, correlate linearly with the differences in the heat of formation of isodesmic reactions. These constants also correlate with the charges on the acid moiety of the bicyclooctane acids and their anions, and with the hydrogen net charge on the protonated quinuclidines. For all cases, the NO2 was the poorest correlated substituent. Copyright © 2003 John Wiley & Sons, Ltd. [source] The dependence on temperature and concentration of 129Xe NMR chemical shift values of organoxenon(II) salts [RXe][Y] and of the parent molecule XeF2MAGNETIC RESONANCE IN CHEMISTRY, Issue 6 2006Vadim V. Bardin Abstract The dependence of the 129Xe NMR chemical shift value of XeF2 on temperature and concentration was determined in a variety of prototypic media: in acidic (anhydrous HF, aHF), nonprotic but polar (dichloromethane), and basic (CD3CN-EtCN, 1:3 v/v) solvents. The 129Xe NMR spectra of a representative series of organoxenon(II) salts [RXe][Y] (R = C6F5, heptafluoro-1,4-cyclohexadien-1-yl (cyclo -1,4-C6F7), pentafluoro-1,4-cyclohexadien-3-on-1-yl (cyclo -3-O-1,4-C6F5), CF2 = C(CF3), (CF3)2CFC,C, C4H9C,C; Y = BF4, AsF6) in aHF showed, compared with XeF2aHF, a quantitatively less distinct but qualitatively related dependence of ,(129Xe) vs temperature. The dependence of their ,(129Xe) values on concentration in aHF is negligible. An explanation for the different behavior of [RXe][Y] and XeF2 is offered. Copyright © 2006 John Wiley & Sons, Ltd. [source] Non-empirical calculations of NMR indirect carbon,carbon coupling constants.MAGNETIC RESONANCE IN CHEMISTRY, Issue 2 2005Part 1, a practical guide to structural elucidation, saturated carbocycles: a reference data set Abstract Carbon,carbon spin,spin coupling constants, J(C,C), calculated at the SOPPA level for 50 mono-, bi- and polycycloalkanes in 10 previous papers are put in order and discussed on unified grounds. Basic structural trends of J(C,C) established in the original publications are summarized and briefly outlined for the representative series. Many unknown couplings are predicted with high reliability, and this provides a good reference data set and a practical guide to the structural elucidation of saturated carbocycles by means of J(C,C) coupling constants. Copyright © 2004 John Wiley & Sons, Ltd. [source] Influence of the C,H· · ·N intramolecular interaction on the spatial structures and 1H and 13C NMR parameters of heteroaryl vinyl ethers and sulfidesMAGNETIC RESONANCE IN CHEMISTRY, Issue 8 2003Andrei V. Afonin Abstract A complete analysis of the 1H and 13C spectra of the representative series of heteroaryl vinyl ethers and sulfides and heteroaryl styryl sulfides was carried out. The electronic and spatial structures of these compounds are discussed. It was shown that the C,H· · ·N intramolecular interactions in the investigated molecules influence significantly the spectral parameters and the conformational equilibrium. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||