Titanium and zirconium complexes with sterically hindered aryl-substitutediminophosphoranato ligands

The benzyliminophosphorane 4-(BuC6H4CH2P)-C-t(Ph)(2) =NC6H2Me3-2,4,6 reacte d with TiCl4 or ZrCl4 to give the N-donor adducts, MCl4{4-(BuC6H4CH2P)-C-t( Ph)(2) =NC6H2Me3-2,4,6}. Whereas the zirconium compound proved unreactive, solutions of the titanium analogue at 10-20 degreesC slowly underwent C-H a ctivation to give the phosphoranato complex TiCl3{4-(BuC6H4CHP)-C-t(Ph)(2)= NC6H2Me3-2,4,6}. The trichloro complexes MCl3{4-ButC(6)H(4)- CHP(Ph)(2)=NC6 H2Me3-2,4,6} were also accessible from Li[4-(BuC6H4CHP)-C-t(Ph)(2)=NC6H2Me3 -2,4,6] and MCl4 (M = Ti or Zr). The reaction of 4-(BuC6H4CH2P)-C-t(Ph)(2) =NC6H2Me3-2,4,6 with Zr(NMe2)(4) in refluxing toluene led to Zr(NMe2)(3)- { 4-(BuC6H4CHP)-C-t(Ph)(2)=NC6H2Me3-2,4,6}. The compound is fluxional in solu tion. Treatment with an excess of Me-3- SiCl led to silylation of the ligan d to give ZrCl4{4-(BuC6H4CH)-C-t(SiMe3)P(Ph)(2)=NC6H2Me3-2,4,6}. The struct ures of 4-(BuC6H4CH2P)-C-t(Ph)(2)=NC6H2Me3-2,4,6 and Zr(NMe2)(3){4-(BuC6H4C HP)-C-t(Ph)(2) =NC6H2Me3-2,4,6} were determined by X-ray diffraction.