Intramolecular hydrogen BOND С–НВ···N in 1,1'-divinyl-2,2'-diimidazolyl According to the data of аb initio calculations and QTAIM analysis
A. V. Vashchenko, A. V. Afonin
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk
Keywords: intramolecular hydrogen bonds С–H···N, ab initio calculation, QTAIM, RDG analysis
Abstract
By non-empirical ab initio quantum chemical calculation the spatial structure of 1,1'-divinyl-2,2'-diimidazolyl is determined and the formation of intramolecular hydrogen bonds of the С–H···N type in it is established. It is evidenced by energy preference for the conformation in which there is a short contact between the α-proton of the vinyl group and the endocyclic nitrogen atom (2.28 Å), creating favorable conditions for the formation of a six-membered chelate cycle. An analysis of the topological characteristics of the electron density and the reduced electron density gradient also give evidence in favor of the formation of a weak intramolecular hydrogen bond C–H···N. The estimation of the hydrogen bond energy by the Espinosa method results in a value below 3 kcal/mol.
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