Intermolecular H-bond of solvent molecule with nitroxide radical using ab initio MO calculations
2002; Elsevier BV; Volume: 615; Issue: 1-3 Linguagem: Inglês
10.1016/s0022-2860(02)00222-3
ISSN1872-8014
AutoresTakao Otsuka, W. Motozaki, Kiyoshi Nishikawa, Kazunaka Endo,
Tópico(s)Magnetism in coordination complexes
ResumoIn order to reproduce the negative spin density on the proton of proton donor solvent molecules (CHCl3 and CH3OH) induced by di-tert-nitroxide (DTBN, [(CH3)3C]2NO) radical in liquid NMR experiment, we calculated four types of geometrical arrangements for the intermolecular H-bond of the proton donor molecule (X–H) with the model radicals ((CH3)2NO, DMNO) and DTBN using the ab initio gaussian program. We considered the four types (π(O), π(N), σ(θ), and π(θ)) of H-bond bimolecular systems. The calculations for potential energy surface of the four types of bimolecular H-bond systems were performed using unrestricted Hartree–Fock MO method with STO-3G and 6-31G∗∗ basis set. We obtained the reasonable structure of the π(O) H-bond complex that reproduces the negative spin density on the proton of CHCl3 and CH3OH molecules and the positive spin density on the carbon of CHCl3 in NMR experiment.
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