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Correlation between proton transfer and 35Cl NQR frequency as well as molecular geometry of chloranilic acid in co-crystals with some organic bases

✍ Scribed by Tetsuo Asaji; Janez Seliger; Veselko Žagar; Hiroyuki Ishida


Publisher
John Wiley and Sons
Year
2010
Tongue
English
Weight
153 KB
Volume
48
Category
Article
ISSN
0749-1581

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✦ Synopsis


Abstract

Proton transfer in hydrogen‐bonded organic co‐crystals of chloranilic acid with some organic bases was investigated by nuclear quadrupole resonance (NQR) spectroscopy. The ^35^Cl NQR frequencies of chloranilic acid molecule as well as ^14^N NQR frequencies of the organic base molecule were measured with the conventional pulse methods as well as double‐resonance methods, respectively. The extent of proton transfer in the O···H···N hydrogen bond was estimated from Townes–Dailey analysis of the ^14^N NQR parameters. The ^35^Cl NQR frequency and molecular geometry of chloranilic acid are correlated to the extent of proton transfer in the protonation process of the organic base molecule. It is shown that the hydrogen bond affects the π‐electron system of chloranilic acid. Geometry dependence of the O···H···N hydrogen bond, i.e. the HN valence bond order versus the hydrogen‐bond geometry correlation is also discussed. Copyright © 2010 John Wiley & Sons, Ltd.