Synthesis, characterization, crystal structure, solvatochromism, fluorescence and electrochemical studies of new organometallic platinum complexes, kinetic investigation of oxidative addition reaction

Abstract

A new organoplatinum(II) complex containing 2,2′-biquinoline ligand (biq) was synthesized by the reaction of [Pt(p-MeC6H4)2(SMe2)2] with 2,2′-biquinoline in a 1:1 molar ratio. In this complex the ligand was coordinated to metal via the chelating nitrogen donor atoms. Also, platinum(IV) complex was obtained by the oxidative addition reaction of the methyl iodide with the platinum(II) complex in acetone. The platinum complexes have been found to possess 1:1 metal to ligand stoichiometry and the molar conductance data revealed that the metal complexes were non-electrolytes. The platinum(II) and platinum(IV) complexes exhibited square planar and octahedral coordination geometry, respectively. The emission spectra of the platinum(II) and platinum(IV) complexes were studied in dichloromethane. Furthermore, electrochemical properties of the metal complexes were investigated in dimethylformamide (DMF) solvent at 150 mV s−1 scan rate. The ligand and metal complexes showed both reversible and irreversible processes at this scan rate. The complexes have been characterized by IR, 1H NMR, UV/Vis, elemental analysis and conductometry. The crystal structure of the platinum(II) complex containing 2,2′-biquinoline has been determined by single crystal X-ray diffraction. Moreover, kinetic studies of the oxidative addition reaction of methyl iodide with the platinum(II) complex in different temperatures were investigated. It was indicated that the reaction occurred by the SN2 mechanism. The rate of reaction in two different solvents was compared and the activation parameters were determined.