Conformational study of the (z)-[(2-iminoethylidone)silyl]amine at the MP2, DFT and G2MP2 levels

Abstract

(z)-[(2-Iminoethylidone)silyl]amine has been studied extensively as a model involved in intramolecular hydrogen bonding (HB) assisted by π-electrons resonance. In order to evaluate the stability and the nature of intramolecular HB, all of its possible tautomeric structures (imine and amine) were probed at B3LYP/6-311++G**, MP2/6-311++G**, and G2MP2 levels of theory. The calculated geometrical parameters and conformational analysis in gas phase and water solution indicated that the (z)-1-(2-iminoethylidene) silane amine conformers of this compound were more stable than the others. This stability is mainly due to the formation of an N⋯H−N intramolecular HB and the position of Si atom in these conformers. The “atoms in molecules” theory of Bader was used to analyze critical points and to study the nature of hydrogen bond in these systems. Natural bond orbital (NBO) analysis was also performed for better understanding the nature of intramolecular interactions. The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) with frontier orbital gap are presented. The result showed that N⋯H−N intramolecular HB in the mentioned compound possesses a bonding character.