Ligand Effects on the Rate and Mechanism of Solvent Exchange at Rhodium(III) and Iridium(III)

The rate constants and activation parameters for solvent exchange for a series of RhIII and IrIII complexes of the form [M(H2O)6]3+ (M = Rh or Ir) and [Cp*M(S)3]2+ (M = Rh or Ir, and S = H2O, MeCN, or Me2SO) have been determined by NMR spectroscopy as a function of free-solvent concentration, temperature, and pressure, and the mechanisms for the respective exchange processes have been inferred