SYNTHESIS, CHARACTERIZATION AND SOLUTION PROPERTIES OF ORGANORHODIUM COMPLEXES DERIVED FROM RHODOXIMES WITH ONE OR 2 DIPHENYLBORON MOIETIESIN THE OXIME BRIDGES

The reaction between methylrhodoxime, CH3Rh(DH)(2)L (L = N-Melm or Py) , and diphenylborinic anhydride affords derivatives containing either one or two diphenylboryl bridges, depending on the ratio complex:diphe nylborinic anhydride. Kinetic studies show that the insertion of the d iphenylboryl bridges is a two-step process involving the formation of a relatively stable intermediate. The X-ray structure of CH3Rh(DH)(DBP h(2))N-MeIm shows that the axial phenyl faces the N-MeIm, whereas the main conformation in solution, as inferred from H-1 NMR spectra, has t he axial phenyl facing the methyl. The bis(diphenylborylated) derivati ves are less stable than those of the corresponding cobaloximes, and a dopt a conformation with trans axial phenyls.