Chemistry of 2H-azaphosphirene complexes, 13 - Phosphorus-bridged dinuclear tungsten amino(aryl)carbene complexes - New precursors for (2H-azaphosphirene)tungsten complexes bearing a sigma-P-bonded Cp* group

The first syntheses of pentacarbonyl[2-(pentamethyl-2,4-cyclopentadien-1-yl )-2H-azaphosphirene]tungsten complexes are reported, using a one-pot reacti on of dichloro(pentamethyl-2,4-cyclopentadien-1-yl)phosphane (Cp*PCl2) with triethylamine and {[amino(aryl) carbene]pentcarbonyltungsten(0)}. [Pentame thyl-2,4-cyclopentadien-1-yl]phosphane-diyl-bridged dinuclear carbene compl exes are formed as long-lived intermediates, which, by elimination and rear rangement reactions, led to the final products. If traces of water were pre sent, then by-products were formed; in one case, a dinuclear carbene comple x with a P(Cp*)-O-P(Cp*) bridging unit was isolated. Under ordinary reactio n conditions 2H-azaphosphirene complexes are slowly transformed into {penta carbonyl[chloro (pentamethyl-2,4-cyclopentadien-1-yl) phosphane]tungsten(0) }. NMR-spectroscopic and single-crystal X-ray structural data of some dinuc lear carbene complexes and 2-(pentamethyl-2,4-cyclopentadien-1-yl)-2H-azaph osphirene complexes are presented.