Synthesis, structural characterization, and reactivity of late transition-metal complexes bearing linked cyclopentadienyl-carboranyl ligands

Late transition-metal complexes bearing linked cyclopentadienyl/indenyl carboranyl ligands were synthesized and their reactivities were examined. Reaction of Li-2[Me2C(L)(C(2)BioH(10))] (L = C5H4, C9H6, Me2NCH2CH2C5H3) with MCl2(PPh3)(2) in Et2O afforded [eta(5):sigma-Me2C(C5H4)(C2B10H10)]M(PPh3) (M = Co (4), Ni (5)), [eta(5):sigma-Me2C(C9H6)(C2B10H10)]M(PPh3) (M = Co (6), Ni (7)), and [eta(5):sigma-Me2C(Me2NCH2CH2C5H3)(C2B10H10)]Ni(PPh3) (8). Treatment of 4 or 5 with 2,6-dimethylphenylisocyanide, N-heterocyclic carbene (NHC), PCy3, or 1,2-bis(diphenylphosphino)ethane (dppe) gave the corresponding PPh3 displacement complexes [eta(5):sigma-Me2C(C5H4)(C2B10H10)]M(2,6-Me(2)C(6)H3NC) (M = Co (9), Ni (10)), [eta(5):sigma-Me2C(C5H4)(C2B10H10)]M[1,3-(2,6-i-Pr2C6H3)(2)C3N2H2] (M = Co (11), Ni (12)), [eta(5):sigma-Me2C(C5H4)(C2B10H10)]Ni(PCy3) (13), or {[eta(5):sigma-Me2C(C5H4)(C2B10H10)]Co}(2)(dPPe) (14), respectively. These complexes were characterized by various spectroscopic techniques and elemental analyses. The molecular structures of 4-14 were further confirmed by single-crystal X-ray analyses.