Alireza Akbari - Chemistry Department, Payame Noor University, ۱۹۳۹۵-۴۶۹۷ Tehran, Iran

The thermodynamic parameters and equilibrium constant for displacement of dimethy sulfide by3-carboaldehyde pyridine as N-donor ligandin cis-[Pt(4-MeC6H4)2(SMe2)2] complex have beenmeasured using UV-vis spectroscopy in acetone, dichloromethane and benzene at varioustemperatures (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, thevalues of enthalpy and entropy changes have been positive and decreased as the donor number ofthe solvents decreased.

Platinum; thermodynamic; 3-carboaldahyde pyridine; donor number