η 2-Alkynyl and Vinylidene Transition Metal Complexes. 6. Reaction of Tungsten Vinylidene Complexes with Chlorophosphines as Nucleophile. Preparation and Crystal Structural Analysis of Neutral η 2-Phosphinovinyl Complexes

The reaction of vinylidene complexes [(η 5-C5H5)(CO)(NO)WCCHR] [R = H (1a), CH3 (1b), C6H5 (1c)] with chlorodiphenylphosphine (2) leads to neutral [R = H (3a), CH3 (3b), C6H5 (3c)]. Analogously the reaction of chlorodi-tert-butylphosphine (4) with [(η 5-C5H5)(CO)(NO)WCCH2] (1a) gives rise to chloro(η 5-cyclopentadienyl)nitrosyl(η 2-di-tert-butylphosphinovinyl)tungsten (5). The formation of these metallacyclopropane rings is rationalized by the nucleophilic attack of chlorophosphine on the Cα carbon of the vinylidene, followed by substitution of the carbonyl ligand. Single-crystal X-ray diffraction data of 3a−c and 5 are reported.