Studies on [VCl3(OPMe2Ph)(PMe2Ph)2]. Part 2. Kinetic and mechanistic studies on the reaction of trans,mer-[VCl3(OPMe2Ph)(PMe2Ph)2] with 2,2′-bipyridine or Et2PCH2CH2PEt2 at 25 °C

Abstract

The kinetics of the reactions between trans,mer-[VCl₃(OPMe₂Ph)(PMe₂Ph)₂] and L–L = 2,2′-bipyridine or Et₂PCH₂CH₂PEt₂ to give mer-[VCl₃(OPMe₂Ph)(L–L)] have been studied in tetrahydrofuran (thf) at 25 °C. Previous proposals that in solution the reactant is the solvento-species [VCl₂(OPMe₂Ph)(PMe₂Ph)(thf)₂]⁺ have been substantiated by kinetic studies which demonstrate that chloride must bind to the reactant prior to interaction with the substrates. The kinetics has been interpreted in terms of a series of associative-interchange steps. Strong evidence for the associative mechanism comes from the observation that the solvento-species does not react with L–L, a pattern which is inconsistent with a dissociative mechanism.