Theoretical study on the antitumor properties of Ru(II) complexes containing 2-pyridyl, 2-pyridine-4-carboxylic acid ligands

[Ru(bipy)(2)(CppH)](2+) (1), [Ru(bipy)(2)(Cpp-NH-Hex-COOH)](2+) (2), [Ru(dppz)(2)(CppH)](2+) (3) and [Ru(dppz)(2)(Cpp-NH-Hex-COOH)](2+) (4) were calculated by Hartree-Fock (HF), Density Functional Theory (DFT) hybrid B3LYP and Moller-Plesset Perturbation (MPn n = 2,3) theory method and CEP-4G, CEP-31G, CEP-121G, LANL2DZ, LANL2MB, SDD basic sets and a mixed basic set with the keyword GEN in gas phase and water. Structure parameters obtained from optimized structures were compared with experimental parameters. M062X/(6-31G(d))(CEP-4G) level was taken into account for the most appropriate calculation level. IR, UV VIS and NMR spectrums were examined for structural characterization. The optimal structure was identified via structure parameters, IR, UV VIS and NMR spectrums. For the most compatible structure, the highest molecular orbital energy (E-HOMO) which one of the most effective chemical determiners on the antitumor activity of the complexes, the lowest molecular orbital energy (E-LUMO), LUMO-HOMO energy gap, hardness (eta), softness (sigma), electronegativity (chi), chemical potential (mu), electrophilicity index (omega), molar volume (V), dipole moment (DM), total negative charge (TNC), enthalpy (H), entropy (S) and total energy (E) were calculated. The causes of anticancer activity of the complexes have been studied. (C) 2017 Elsevier B.V. All rights reserved.