Kinetics of Exchange of Dimethylsulfoxide between Hexakis(dimethylsulfoxide)chromium(III) and Solvent: Pressure Effect and Mechanism

For the exchange of all six dimethylsulfoxide (DMSO) ligands in Cr(DMSO) 6 3+ with perdeuterated DMSO solvent, the first-order rate constant (75°) = 5.5 × 10 −5 s −1 , while ΔH* = 23.1 kcal mol −1 , ΔS* = − 11.8 cal deg −1 mol −1 , and ΔV* = − 11.3 cm 3 mol −1 . These and other data are indicative of an associative interchange mechanism for substitution in Cr(III) DMSO complexes in DMSO.