Reactions of alpha-lithiated phosphinimines with PhCN; The crystal structure of [K{N(H)C(Ph)C(H)P(Ph)(2)=NSiMe3}(tmen)](2) (tmen=Me2NCH2CH2NMe2)

Treatment of the alpha-lithiated phosphinimine Li{CH(R')P(R)(2)=NSiMe3} with benzonitrile yielded (via a trimethylsilyl or hydrogen 1,3 C --> N shift) the trimethylsityliminophosphoranylenamidolithium complex Li{N(R')C(Ph)C(H)P(R)(2)=NSiMe3} (R = Me, R' = SiMe3 1; R = Ph, R' = SiMe3 2; or R = Ph, R' = H 3), Complex 2 was transformed into the corresponding potassium complex 4 by an exchange reaction with KOBut. Crystallisation of 4 from hexane in the presence of Me2NCH2CH2NMe2 (tmen) gave the tmen adduct 5 and a trace of the partially hydrolysed product [K{N(H)C(Ph)C(H)P(Ph)(2)=NSiMe3}(tmen)](2) 6, which was characterised by a single crystal X-ray diffraction study as a dinuclear complex with each of the two potassium atoms in a different co-ordination environment. Complex 1 or 2 was hydrolysed to form the neutral iminophosphoranylenamine N(SiMe3)C(Ph)C(H)P(R)(2)N(SiMe3)H 7 or 8, which showed (H-1 NMR spectroscopy) the presence of hydrogen bonds.