METHYLENEPHOSPHANYL COMPLEXES OF CHROMIUM, MOLYBDENUM, TUNGSTEN, IRON AND NICKEL - SYNTHESIS AND REACTIVITY

The reaction of the functionalized P/C double bond systems X - P = C(R)SiMe3 [R = SiMe3 and X = Cl (1a), Cp* (5a) or R = Ph and X = Br (1b), Cp* (5b)] with alkali carbonylmetallates or carbonyl complexes of group 6, 8, and 10 metals leads to the formation of the transition metal-substituted phosphaalkenes [{M}-P=C(R)SiMe3 3a-j and 4a-i], in which the P - C fragment acts as a one-electron donor. Depending on the nucleophilicity of the transition metal anion used, but also on the methylene carbon substituents [1a: (SiMe3)2; 1b: (Ph)-SiMe3], a different stability of the (methylenephosphanyl)-metal complexes is observed, which results in a broad spectrum of reactivities. As demonstrated by the reactions of the (methylenephosphanyl)metal complexes with sulfonic acid derivatives (10a-c), diverse transition metal complexes (11a-c), as well as chalcogenes (14a-c, 15), a change in the reactivity is observed, indicating a transition from an olefinic to a carbenic character of the methylenephosphane. In comparison to the phenyl-substituted derivatives 4a-i the bis(trimethyl)-substituted species 3a-j exhibit an increased reactivity. This is reflected in the easy decarbonylation of 3a-d to the phosphavinylidene complexes 12a-d.