Home About us Contact
|
Home About us Contact | ||
|
|
||
Heteronuclear Multiple Bond Correlation (heteronuclear + multiple_bond_correlation)
Selected AbstractsDirection of Isomerization of 5-Hydroxy-3-propargylthio-1,2,4-triazines According to 1H/15N Heteronuclear Multiple Bond Correlation (HMBC) Spectra.CHEMINFORM, Issue 48 2006V. Yu. Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Preparation of carbonated natural rubberJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2006Seiichi Kawahara Carbonated natural rubber was prepared from deproteinized natural rubber with supercritical carbon dioxide, in which the deproteinization of natural rubber was performed in the latex stage with urea in the presence of a surfactant. The deproteinized natural rubber was epoxidized with peracetic acid in the latex stage, and this was followed by depolymerization with peroxide to prepare liquid epoxidized natural rubber. The liquid epoxidized rubber was incubated with supercritical carbon dioxide with lithium bromide as a catalyst at various temperatures and pressures. The product was proved to be carbonated natural rubber by means of Fourier transform infrared, 1H NMR, 13C NMR, two-dimensional 1H,1H correlation, two-dimensional 1H,13C correlation, and two-dimensional heteronuclear multiple bond correlation. [source] Synthesis of rhodium(III) complexes with tris/tetrakis-benzimidazoles and benzothiazoles,quick identification of cyclometallation by nuclear magnetic resonance spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 8 2009N. Chandrashekhar Abstract Reactions of rhodium(III) halides with multidentate N,S -heterocycles, (LH3) 1,3,5-tris(benzimidazolyl)benzene (L1H3; 1), 1,3,5-tris(N -methylbenzimidazolyl) benzene (L2H3; 2) and 1,3,5-tris(benzothiazolyl)benzene (L3H3; 3), in the molar ratio 1:1 in methanol,chloroform produced mononuclear cyclometallated products of the composition [RhX2(LH2)(H2O)] (X = Cl, Br, I; LH2 = L1H2, L2H2, L3H2). When the metal to ligand (1,3 or 1,2,4,5-tetrakis(benzothiazolyl)benzene [L4H2; 4]) molar ratio was 2:1, the reactions yielded binuclear complexes of the compositions [Rh2Cl5(LH2)(H2O)3] (LH2 = L1H2, L2H2, L3H2) and [Rh2X4(L4)(H2O)2] (X = Cl, Br, I). Elemental analysis, IR and 1H nuclear magnetic resonance (NMR) chemical shifts supported the binuclear nature of the complexes. Cyclometallation was detected by conventional 13C NMR spectra that showed a doublet around ,190 ppm. Cyclometallation was also detected by gradient-enhanced heteronuclear multiple bond correlation (g-HMBC) experiment that showed cross-peaks between the cyclometallated carbon and the central benzene ring protons of 1,3. Cyclometallation was substantiated by two-dimensional 1H1H correlated experiments (gradiant-correlation spectroscopy and rotating frame Overhauser effect spectroscopy) and 1H13C single bond correlated two-dimensional NMR experiments (gradient-enhanced heteronuclear single quantum coherence). The 1H15N g-HMBC experiment suggested the coordination of the heterocycles to the metal ion via tertiary nitrogen. Copyright © 2009 John Wiley & Sons, Ltd. [source] Assignments of 1H and 13C NMR spectral data for ondansetron and its two novel metabolites, 1-hydroxy-ondansetron diastereoisomersMAGNETIC RESONANCE IN CHEMISTRY, Issue 10 2006Mingyu Duan Abstract Assignments of 1H and 13C NMR chemical shifts were made by means of heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) experiments for ondansetron, and by means of 1H- 1H correlation spectroscopy (1H- 1H COSY) and two-dimensional nuclear Overhauser effect spectroscopy (NOESY) experiments for two novel metabolites (M1 and M2) of ondansetron. These two metabolites were isolated for the first time from Mucor circinelloides. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||