Synthesis of new platinum(IV) complexes through breaking disulfide bond; crystal structure determination, electrochemical, photoluminescence and DNA interaction investigation.

Graphical abstract Two new platinum(IV) complexes containing 2,2′-dithiopyridine were synthesized. The obtained platinum(IV) complexes exhibited distorted octahedral geometry. The crystal structure of the arylplatinum(IV) complex has been determined by single crystal X-ray diffraction. The interaction of these complexes with calf thymus DNA was investigated. Highlights • Two new platinum(IV) complexes were synthesized. • The crystal structure of the arylplatinum(IV) complex has been determined. • The interaction of these complexes with calf thymus DNA was investigated. • The enthalpy and entropy of interaction of the complexes and DNA were calculated. • Fluorescence, UV–Vis and electrochemistry of the complexes were investigated. Abstract New platinum(IV) complexes containing N 2 S 2 donor atoms were synthesized by the reactions of [Pt(p -MeC 6 H 4) 2 (SMe 2) 2 ] and [PtCl 2 (DMSO) 2 ] with 2,2′-dithiopyridine (dtp) in 1:1 M ratio. In these reactions, 2-mercaptopyridine (mpy) ligands were formed through the cleavage of the disulfide bond in 2,2′-dithiopyridine. The mpy ligands were coordinated to the platinum center via the nitrogen and sulfur atoms and the obtained platinum(IV) complexes exhibited octahedral geometry. The complexes were characterized by FT-IR, 1H NMR, UV–Vis, elemental analyses and conductometry. The crystal structure of the arylplatinum(IV) complex containing C 2 N 2 S 2 donor atoms was determined by single crystal X-ray diffraction. The obtained molar conductance values revealed that the platinum(IV) complexes were nonelectrolytes. The interactions of the complexes with calf thymus DNA (CT-DNA) were investigated by absorption and fluorescence spectroscopy, cyclic voltammetry and viscometry methods. The intrinsic binding constants (K b) of the complexes with CT-DNA, obtained from UV–Vis absorption data, were 9.60 × 104 M−1 and 11.56 × 104 M−1. Furthermore, the enthalpy and entropy of the interaction between the platinum(IV) complexes and CT-DNA were calculated. The obtained data revealed positive enthalpy and entropy changes indicating a hydrophobic interaction between these complexes and CT-DNA. [ABSTRACT FROM AUTHOR]