Dimethyl sulfide for 3-carboaldehyde pyridine displacement in a platinum(II) complex: Donor number effect

The thermodynamic parameters and equilibrium constant for displacement of dimethy sulfide by 3-carboaldehyde pyridine as N-donor ligandin cis-[Pt(4-MeC6H4)2(SMe2)2] complex have been measured using UV-vis spectroscopy in acetone, dichloromethane and benzene at various temperatures (T=15-20 °C), and compared with my previously reported reactions. ΔHo (KJ.mol- 1) of the mentioned reaction in acetone has been 7.158 while obtained less in dichloromethane (4.109 ) and more in benzene(9.96). The entropy of the reaction has been obtained 86.86 J.mol^- 1.K^-1 in acetone, while calculated less in CH2Cl2 (73.29 J.mol^-1.K^-1) and more in the last solvent (97.40 J.mol^-1.K^-1). Furthermore, the Gibbs energy, ΔG (J.mol^-1), of the reaction obtained- 18738.79, -17741.55 and -19043.06 respectively, with the same order. In all three solvents, the values of enthalpy and entropy changes have been positive and decreased as the donor number of the solvents decreased.