Intramolecular hydrogen bond C-H⋯N in 1,1′-divinyl-2,2′-diimidazolyl according to the data of ab initio calculations and QTAIM 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 C-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 A), 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.