Studies of metallocarboranes incorporating the early transition metals

Abstract

The synthesis and characterization of several new metallocarboranes incorporating the early transition metals is described. Complexes of the formula (M(II)C2B10H10R2)2)(2-) (M = Ti, V, Cr, Mn, R = H; M = Ti, Zr, Hf, V, R = CH3) are reported as well as the mixed-ligand titanacarboranes (CxHxTiC2BnHn+2)m- (x = 5, n = 10, m = 1; x = 8, n = 9 or 10, m = 0 or 1). Magnetic studies were performed with the paramagnetic vanadium, chromium and manganese complexes. The zirconium and hafnium metallocarboranes were found to undergo a facile polyhedral rearrangement in solution. The complexes are discussed in terms of the degree of formal polyhedral electron deficiency and the applicability of electron counting rules to this unique class of organometallic compounds. (Author)