Kinetics of direct bimolecular substitution reaction of a <i>cis</i>-platinum(II) complex with piperidine in water/alcohol mixtures

Abstract

Kinetics of direct bimolecular substitution reaction of <i>cis</i>-[Pt(SEt₂)₂ Cl₂] with piperidine has been studied in water-methanol,-ethanol and - 2-propanol mi xtures. Modeling of second order rate constants with respect to quasi-independent solvent parameters such as π<i>* </i>(dipolarity/polarizability), α(HBD acidity) & β ( HBA basicity) has been carried out. Single-parameter models are not sufficient to explain the observed anomaly that occurs in the reaction rate. Because of opposite effects of π<i>* </i>and α, β on the reaction rate, this behaviour could be understood better using dual-parameter models of these parameters. Coefficients of parameters in final models show that dipolarity/polarizability

parameter is more effective than the others in this reaction. Less negative effects of α on the reaction rate compared to β indicate that a HBD interaction could exist between the complex and protic solvents.