Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Study of hydrogen bonds of hypophosphorous acid by 1H, 2H, 31P, and 15N NMR spectroscopy under slow exchange conditions. / Golubev, N. S.; Asfin, R. E.; Smirnov, S. N.; Tolstoi, P. M.
в: Russian Journal of General Chemistry, Том 76, № 6, 01.06.2006, стр. 915-924.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Study of hydrogen bonds of hypophosphorous acid by 1H, 2H, 31P, and 15N NMR spectroscopy under slow exchange conditions
AU - Golubev, N. S.
AU - Asfin, R. E.
AU - Smirnov, S. N.
AU - Tolstoi, P. M.
PY - 2006/6/1
Y1 - 2006/6/1
N2 - The NMR spectra of solutions containing partially deuterated anhydrous hypophosphorous acid (H2POOH) and its complexes with organic bases as proton acceptors were obtained in CD2Cl2 in the temperature range 183-253 K. Under these conditions, the state of slow exchange is achieved, as evidenced by the fine spin-spin and isotope (H/D) structure of the NMR signals. The formation and strengthening of the hydrogen bond by the OH group result in strong shielding of the 31P nucleus and decrease the spin-spin coupling constants of nuclei in the PH2 group. Saturation of these effects occurs in going from proton to base. Direct and long-range effects of H/D substitution in the OH and PH groups on the H, 31P, and 15N chemical shifts in complexes were measured. The signs of these effects were explained in terms of a simplified model of dynamic interaction of covalent and hydrogen bonds. The kinetics of the interconversion of a cyclic H2POOH dimer and a zwitterionic complex with pyridine were studied by dynamic 1H NMR, and thermodynamic and kinetic parameters of the process were measured. A hypothetical mechanism of the reaction with the transition state close to an open-chain dimer with one hydrogen bond was proposed.
AB - The NMR spectra of solutions containing partially deuterated anhydrous hypophosphorous acid (H2POOH) and its complexes with organic bases as proton acceptors were obtained in CD2Cl2 in the temperature range 183-253 K. Under these conditions, the state of slow exchange is achieved, as evidenced by the fine spin-spin and isotope (H/D) structure of the NMR signals. The formation and strengthening of the hydrogen bond by the OH group result in strong shielding of the 31P nucleus and decrease the spin-spin coupling constants of nuclei in the PH2 group. Saturation of these effects occurs in going from proton to base. Direct and long-range effects of H/D substitution in the OH and PH groups on the H, 31P, and 15N chemical shifts in complexes were measured. The signs of these effects were explained in terms of a simplified model of dynamic interaction of covalent and hydrogen bonds. The kinetics of the interconversion of a cyclic H2POOH dimer and a zwitterionic complex with pyridine were studied by dynamic 1H NMR, and thermodynamic and kinetic parameters of the process were measured. A hypothetical mechanism of the reaction with the transition state close to an open-chain dimer with one hydrogen bond was proposed.
UR - http://www.scopus.com/inward/record.url?scp=33747477073&partnerID=8YFLogxK
U2 - 10.1134/S1070363206060119
DO - 10.1134/S1070363206060119
M3 - Article
AN - SCOPUS:33747477073
VL - 76
SP - 915
EP - 924
JO - Russian Journal of General Chemistry
JF - Russian Journal of General Chemistry
SN - 1070-3632
IS - 6
ER -
ID: 36464880