Reactivity of Terminal, Electrophilic Phosphinidene Complexes of Molybdenum and Tungsten. Nucleophilic Addition at Phosphorus and P−P Bond Forming Reactions with Phosphines and Diphosphines

Abstract

Reaction of the terminal electrophilic phosphinidene complexes [Cp*M(CO)3{PN(i-Pr)2}][AlCl4] (3, M = Mo; 4, M = W) with PEt3 results in replacement of a metal carbonyl by the phosphine. The reactions occur via initial nucleophilic attack by the phosphine at the phosphinidene phosphorus, followed by carbonyl loss and migration of the phosphine to the metal. Reactions of 3 and 4 with bis(dimethylphosphino)methane (dmpm) lead to [Cp*M(CO)2{P(N(i-Pr)2)P(Me2)CH2P(Me2)-κ2P1,P4}][AlCl4] (9, M = Mo; 10, M = W), in which one end of the diphosphine coordinates to phosphorus and the other end coordinates to the metal. The reactions proceed by initial nucleophilic attack by one end of the diphosphine at phosphorus, followed by carbonyl loss and coordination of the other end of the ligand to the metal. Compound 3 (M = Mo) reacts with bis(dimethylphosphino)ethane (dmpe) to give the analogous product [Cp*Mo(CO)2{P(N(i-Pr)2)P(Me2)CH2CH2P(Me2)-κ2P1,P5}][AlCl4] (12), in which the two ends of the dmpe ligand coordinate to p...