Polypyridyl-hydrazone based Ruthenium(II) complexes: Spectral and computational analysis

Abstract

New octahedral Ruthenium(II) complexes of the general composition [Ru(bpy)2(L)]Cl containing aroyl hydrazone Schiff base ligands (L) (where bpy = bipyridine, L = 4-((E)-(furan-2-carboylimino)methyl)benzoic acid (L1), 4-((E)-(4-methoxybenzoylimino)methyl)benzoic acid (L2) and 4-((E)-(4-nitrobenzoylimino)methyl)benzoic acid (L3)) have been synthesized. All the three complexes have been characterized by various physico-chemical and spectroscopic methods. The molecular structure of L1 and L2 were determined by single crystal X-ray diffraction method. IR study shows that the substituted aroylhydrazone ligands behave as a monoanionic bidentate O and N donors (L) coordinates to ruthenium via the azomethine nitrogen and the deprotonated amide oxygen. Photophysical and electrochemical studies were carried out and the structures of the synthesized complex were optimized using density functional theory (DFT). The molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energies and Mulliken atomic charges and molecular electrostatic potential (MEP) of the molecules are determined at the B3LYP method and standard 6-311++G (d,p) basis set starting from optimized geometry.