Molecular structure, spectroscopic investigation (FT-IR, 1H NMR, 13C NMR and Mass) and quantum chemical calculations of Ruthenium (II) complex of isoniazid ligand

Abstract

The present study aims at the synthesis of [Ru(CN)₅INH]^3- complex by substitution of cyanide ion in [Ru(CN)₅H₂O]^3- anion by isoniazid (pyridine-4- carboxylic acid hydrazide) (INH) ligand. The reaction has been monitored spectrophotometrically in aqueous medium, by measuring an increase in absorbance at 500 nm (λmax of the light yellow coloured complex), which corresponds to the metal to ligand charge transfer (MLCT) transition, due to the formation of the final substituted complex [Ru(CN)₅INH]^3-. The synthesized complex [Ru(CN)₅INH]^3- has been characterized by ¹H and ¹³C nuclear magnetic resonance, infrared and mass spectral analysis. Quantum mechanical calculations have been performed at DFT level using Becke3-Lee-Yang-Parr (B3LYP) with LanL2DZ basis set. The experimental spectroscopic data has been found to be in good agreement with the calculated results. The Mulliken population analysis on atomic charges, electric dipole moment, polarizability and first order hyperpolarizability values have been evaluated along with hyper conjugative interactions which have been studied with the help of natural bond orbital analysis. Thermodynamic properties like heat capacity, entropy and zero vibrational energy have been analysed at different temperatures.