DIPHENYLBORYLATED DERIVATIVES OF ORGANOCOBALOXIMES AND ORGANORHODOXIMES - SYNTHESIS, SPECTROSCOPIC AND STRUCTURAL CHARACTERIZATION

A series of organometallic complexes derived by organocobaloximes and organorhodoximes in which either one or both the hydrogen bridges have been replaced by BPh2 groups, RM(DH)(DBPh2)N-MeIm and RM((DBPh2)(2) N -MeIm, respectively, have been synthesised and characterised, both in solution and in solid state. H-1 NMR spectra show that they assume dif ferent interconverting conformations in solution. With increasing ster ic bulk of R, the axial phenyls of the BPh2 group tend to face N-MeIm, forcing the latter in an orientation which is quite unusual in organo cobaloximes and causing a lengthening of the Co-N bond. Some possible implications on the strength of the trans Co-C bond are discussed. (C) 1997 Elsevier Science S.A.