Evidence for bond breaking substantially preceding bond making in the mechanisms of spontaneous aquations of penta-aminechloro-chromium(III), -cobalt(III), and -rhodium(III) complexes: crystal and molecular structure of chloropentakis(methylamine)rhodium(III) chloride

Abstract

The Rh–Cl bond is 0.017(2)Å shorter in the crystal structure of [Rh(NH₂Me)₅Cl]Cl₂ than in the structure of [Rh(NH₃)₅Cl]Cl₂; when combined with the corresponding differences of 0.003(3)Å for Co^III and 0.028(2)Å for Cr^III, this explains the trends in the substitution kinetics of these complexes, without a need to invoke changes in mechanisms.