In-vitro cytotoxic activity and theoretical investigations for new mononuclear Pt(IV) and dinuclear Ru(III) with o-phenylenediamine ligand complexes against L20B cell line

Abstract

New mononuclear platinum(IV) and dinuclear ruthenium(III) complexes were synthesized with the o-phenylenediamine (OPD) ligand. The complexes were characterized by different spectroscopic techniques, and DFT calculations and their cytotoxic activity has been investigated in this study. The obtained FT-IR data confirmed that the o-phenylenediamine (OPD) ligand coordinated from the two nitrogen atoms with the platinum(IV) and the Ru(III) metal ions. The mass spectral data confirmed that the platinum(IV) complex was mononuclear, whereas the Ru(III) complex was dinuclear. The magnetic susceptibility measurements indicated that the platinum(IV) complex was diamagnetic, while Ru(III) complex was paramagnetic. UV–vis. measurements showed the peaks of the charge transfer and the (d-d) metal transitions. The DFT and TD-DFT calculations showed that the complexes were stable and the electronic energies are (-521.99 and − 963.59 a.u.) for the Pt(IV) and the Ru(III); respectively, while for the o-phenylenediamine ligand is (-342.96 a.u.), the HOMO energies are (-0.214 a.u.) for the Pt(IV) complex, and (-0.267 a.u.) for the Ru(III) complex, the LUMO energies are (-0.145 a.u.) for the Pt(IV) complex and (-0.183 a.u.) for the Ru(III) complex. The dipoles moment of the complexes are (13.70 and 0.004 Debye); respectively indicating that the complexes are polarized. From all the spectroscopic data, and the bond angles excluded from the DFT calculations the proposed structures of the complexes are distorted octahedral. The prepared complexes' cytotoxicity has been studied and the results showed that the Pt(IV) and the Ru(III) complexes have good cytotoxicity against L20B cell lines with IC50 (169.8 and 204.8 µg); respectively which opens the field for further application as antitumor complexes.