No abstract

An unusual family of three-coordinate, d(8) and d(9) nickel phosphido and phosphinidene complexes containing the chelating 1,2-bis(di-tert-butylphosphino)ethane (dtbpe) ligand and a terminal PR(2)(-) or PR(2-) ligand have been prepared. The complexes (dtbpe)Ni[P(t-Bu)(2)] (2), [(dtbpe)Ni[=P(t-Bu)(2)](+)][PF(6)(-)] (3), [(dtbpe)Ni[=P(H)(dmp)](+)][PF(6)(-)] (5), and (dtbpe)Ni[=P(dmp)] (6) have been structurally characterized by single-crystal X-ray diffraction methods. The three-coordinate d(8) complexes exhibit Ni-P bond lengths and ligand geometries that indicate they participate in symmetry-allowed ligand-to-metal pi bonding involving phosphorus p-electrons and a metal-orbital of pi symmetry that lies in the Ni coordination plane. Compound 6 is a rare example of a late-transition-metal terminal phosphinidene complex.

Reaction of Ir(NO)(PPh3)3 with anhydrous HCl results in addition of 2 equivalents of HCl with formal protonation of the nitrosyl ligand, affording the unusual six-co-ordinate nitroxyl complex cis,trans-IrHCl2(NH=O)(PPh3)2.

Nitrosonium triflate reacts with cold methylene chloride solutions of mer,trans-ReH(CO)3(PPh3)2 (1) with 1,1-insertion of NO+ into the Re-H bond to give the orange nitroxyl complex [mer,trans-Re(NH=O)(CO)3(PPh3)2][SO3CF3] (3) in 86% isolated yield. Use of [NO][PF6] or [NO][BF4] gives analogous insertion products at low temperature, which decompose on warning to ambient temperature to the fluoride complex mer,trans-ReF(CO)3(PPh3)2 (4). A related 1,1-insertion is observed in the reaction of 1 with [PhN2][PF6] in acetone that affords the yellow-orange phenyldiazene salt [mer,trans-Re(NH=NPh)(CO)3(PPh3)2][PF6] (2), which has been characterized by X-ray crystallographic methods. The methyl derivative mer,trans-Re(CH3)(CO)3(PPh3)2 (5) also undergoes a 1,1-insertion reaction with [NO][SO3CF3] to give the nitrosomethane adduct [mer,trans-Re{N(CH3)=O}(CO)3(PPh3)2][SO3CF3] (6) as red crystals in 75% yield. The nitroxyl complex [cis,trans-OsBr(NH=O)(CO)2(PPh3)2][SO3CF3] (8) can be similarly prepared as orange crystals in 52% yield by reaction of cis,trans-OsHBr(CO)2(PPh3)2 (7) with [NO][SO3CF3] in cold methylene chloride solution.