NBO Population Analysis and Electronic Calculation of Four Azopyridine Ruthenium Complexes by DFT Method

Abstract

The molecular structure, the Natural Bond orbital (NBO) and the Time Dependent-DFT of both isomers cis or γ-Cl and trans or δ-Cl of RuCl2(L)2, where L stands respectively for 2-phenylazopyridine (Azpy), 2,4-dimethyl-6-[phenylazo]pyridine (Dazpy), 2-[(3,5-dimethylphenyl)azopyridine] (Mazpy) and 2-pyridylazonaphtol (Nazpy) were calculated with DFT method at B3LYP/LANL2DZ level. The prediction of the frontier orbitals (Highest Occupied Molecular Orbital or HOMO and Lowest Unoccupied Molecular Orbital or LUMO) shows that the most active complexes suitable for electronic reactions are admitted to be the trans isomers. Moreover, δ-RuCl2 (Azpy)2 is discovered to react more actively as photo-sensitizer since its energy gap is the minimum. Besides, electronic structures of all complexes through NBO calculation indicate that Ru-N bonds are made of delocalization of occupancies from lone pair orbital of N atoms to the ruthenium. Moreover, Ru was assumed to have almost the same charge...