A kinetic study of the transmission of ligand effects across the quadruple bond in [Re2Cl8]2–

Abstract

The kinetics of the stepwise replacement of two chlorides by tertiary phosphines and arsines (L) in [Re₂Cl₈]^2– to yield [Re₂Cl₆L₂] has been measured in dichloromethane solution. Only one associative reaction step is observed. Isolation of the intermediate [Re₂Cl₇L]^– complexes allows direct measurement of a second reaction step. The kinetics of the reverse reactions has also been measured and two associative reaction steps are observed. Large ligand-labilising effects are transmitted across the quadruple bond when chloride is substituted by tertiary phosphines and arsines.