Synthesis, Structure, and Coordination Chemistry of P-Acyl-, P-Thiocarbamoyl-, and P-Dithiocarboxyl-Substituted Phosphaalkenes R(X)C−PC(NMe2)2 (R = Ph, tBu, SSiMe3, N(Ph)SiMe3; X = O, S)

Abstract

Reaction of Me3SiPC(NMe2)2 (1) with pivaloyl chloride and benzoyl chloride afforded the acylated phosphaalkenes RC(O)PC(NMe2)2 2a (R = tBu) and 2b (R = Ph). Carbon disulfide and phenyl isothiocyanate were inserted into the P−Si bond of 1 to give the functionalized phosphaalkenes R(X)C−PC(NMe2)2 2c [R(X)C = Me3Si−S(S)C] and 2d [R(X)C = Ph(Me3Si)N(S)C]. Heating 2c and 2d with (CO)5MBr (M = Mn, Re) in toluene at 50−80 °C led to complexes [X = 3c (M = Mn, X = S), 3d (M = Mn, X = NPh), 4c (M = Re, X = S), and 4d (M = Re, X = NPh). The X-ray structure analysis of 2c showed extensive π-delocalization of electron density from phosphorus into the CS group. The structure determination of 4d revealed the molecule as a tricyclic system with an anti orientation of the peripheric four-membered rings. The organophosphorus fragment serves as η2(P,S)-μ(P) bridging ligand, a coordination mode without precedence in phosphaalkene chemistry.