Organonitrogen groups in metal carbonyl complexes. Part IV. Isomeric forms of aza-allyl–allene complexes of molybdenum and tungsten

Abstract

Reactions between [(π-C₅ H₅)M(CO)₃Cl](M = Mo or W) and (p-tolyl)₂C:NLi produce three types of complexes, [(π-C₅H₅)M(CO)₂NC(p-tolyl)₂](I), [(π-C₅H₅)M(CO)₂{(p-tolyl)₂CNC(p-tolyl)₂}](II), and [(π-C₅H₅)M(CO)₂{(p-tolyl)₂CNC(p-tolyl)₂}(p-tolyl)₂CO](III). Two forms of (II; M = W) were isolated in the solid state but a common species was formed in solution. (III) also gave the same solution species together with the free ketone. A mechanism for the formation of the complexes and the biproducts (p-tolyl)₂CO, NCO^–, and CN^– is proposed. All complexes failed to undergo substitution reactions with Ph₃P.