Study of the hydrogen bonding between l-heteroaryl-2- (1-methylpyridinium-2-yl)‎ ethylene cation (HME)‎ and some small molecules

Abstract EN

The theoretical calculations of trans 1-furan-2-yl (1-methylpyridinium-2-yl) ethylene (I) cation and its complexes with HF, CHR3ROH and HR2RO respectively (II, III and IV) were carried out by quantum mechanical method.

The optimized structures of the cation and its complexes (I, II, III and IV) were obtained by the density functional theory DFT at B3LYP5 level of theory using the basis set 6-31G in gas phase and various solvents.

The study shows that the optimized structures of compounds (I, II, III and IV) have the global minimum energy.

Global descriptors such as the dipole moment(μ), molecular orbital energy of HOMO and LUMO levels, ΔE, hardness (η), electronegativity (X)and electrophilicity (ω ) were determined and used to identify the differences in the stability and reactivity of the compounds.

In general the calculated values lead to the conclusion that the stabilities of the compounds according to the values of hardness and energy gap are in sequence II > III > IV > I in various solvents and according sequence II > III > I > IV in gas phase.

The theoretical calculations of UV-Visible for the cation and its complexes with HF, CHR3ROH and HR2RO were carried out by TD-B3LYP5 level of theory using the basis sets 6-31G (d, p) and 6-311G(d, p), and the results were compared with experimental data.