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One- and Two-Dimensional 15N Exchange CP/MAS NMR Studies of the Structure and Electronic Properties of the Intermolecular N—H⋯N Hydrogen Bond in Imidazole Crystal

✍ Scribed by T. Ueda; H. Masui; N. Nakamura

Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
128 KB
Volume
20
Category
Article
ISSN
0926-2040

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✦ Synopsis

The hydrogen bond of the type N-H• • • N in imidazole crystal has been studied by oneand two-dimensional 15 N exchange CP/MAS NMR measurements as well as the powder NMR spectrum. The chemical shift anisotropies for -N and -N< were determined from the powder 1D spectrum. In 2D exchange CP/MAS NMR spectrum, the cross peaks between the 15 N main resonance peaks for -N and -N< were observed, implying that magnetization exchange between -N and -N< takes place. The 1D exchange CP/MAS NMR measurements determined the exchange rate of magnetization at 289 K to be 1.3 and 1.5 s -1 for -N and -N<, respectively. The proton-driven spin-diffusion model interprets the experimental values, and the exchange rate depends strongly on the RF power of the proton decoupling field, suggesting that the magnetization transfer between -N and -N< takes place by the 1 H-driven spin-diffusion mechanism.

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