SYNTHESIS OF GROUP-6 (ARYLOXY)CARBYNE AND PHOSPHONIOCARBYNE COMPLEXES FROM CHLOROCARBYNE PRECURSORS

Displacement of chloride from the group 6 chlorocarbyne complexes Tp'(CO)2M = CCl (M = Mo, W; Tp' = HB[N2C3Me2H]3-) with aryloxide anions produces the neutral (aryloxy)carbynes Tp'(CO)2M = COAr (Ar = Ph, 4-C6H4CH3, 4-C6H4OCH3). Tertiary phosphines (PMe2Ph, PPh3, PCy3) also displace chloride from the tungsten halocarbyne precursor to give the cationic phosphoniocarbynes [Tp'(CO)2W = CPR3][PF6]. Complex 5a, [Tp'(CO)2W = CPMe2Ph][PF6], crystallizes in the triclinic space group P1BAR with unit cell dimensions a = 10.897 (3) angstrom, b = 11.631 (3) angstrom, c = 13.939 (4) angstrom, alpha = 102.96 (2)degrees, beta = 108.79 (2)degrees, gamma = 94.59 (2)degrees, Z = 2, 4954 observed data, R = 0.039 and R(w) = 0.070. Although no one-bond coupling between phosphorus and the carbyne carbon was observed for the PMe2Ph or PPh3 products, the tricyclohexyl derivative displays a small phosphorus-carbon one-bond coupling constant (1J(P-C) = 15 Hz) in its C-13 NMR spectrum. All complexes have been characterized by H-1 and C-13 NMR and IR spectroscopy and by elemental analysis.