Ti and Zr bidentate bis-phosphinimide complexes

Abstract

The diphosphines m-C₆H₄(CH₂Pt-Bu₂)₂1 and m-C₆H₄(CH₂PCy₂)₂2 were prepared and oxidized with Me₃SiN₃ to m-C₆H₄(CH₂(t-Bu₂)PNSiMe₃)₂3 and m-C₆H₄(CH₂(Cy₂)PNSiMe₃)₂4, and subsequently converted to m-C₆H₄(CH₂(t-Bu)₂PNH)₂5 and m-C₆H₄(CH₂(Cy)₂PNH)₂6. Reaction of 5 and 6 with Ti(NMe₂)₄ afforded the yellow compounds m-C₆H₄(CH₂(t-Bu)₂PN)₂Ti(NMe₂)₂7 and m-C₆H₄(CH₂(Cy)₂PN)₂Ti(NMe₂)₂8, and the low abundance by-product m-C₆H₄(CH₂(t-Bu)₂PN)₂TiBr(NMe₂) 9. In a similar manner, the species m-C₆H₄(CH₂(t-Bu)₂PN)₂Zr(NEt₂)₂10 was prepared from Zr(NEt₂)₄. Compounds 8, 9 and 10 were converted to C₆H₄(CH₂(t-Bu)₂PN)₂TiBr₂11, m-C₆H₄(CH₂(Cy)₂PN)₂TiCl₂13 and C₆H₄(CH₂(t-Bu)₂PN)₂ZrCl₂14via reaction with Me₃SiX (X = Br, Cl). Alternatively, m-C₆H₄(CH₂(t-Bu)₂PN)₂TiCl₂12 and 13 were prepared in low yield from reaction of 3 or 4 with TiCl₄. Alkylation of 11 with MeMgBr and PhCH₂MgBr proceeded to give m-C₆H₄(CH₂(t-Bu)₂PN)₂TiMe₂15 and m-C₆H₄(CH₂(t-Bu)₂PN)₂Ti(CH₂Ph)₂16, respectively. The species (m-C₆H₄(CH₂(t-Bu)₂PN)₂)₂Zr 17 was prepared from Zr(CH₂Ph)₄. These synthetic routes are described and the implications for applications in olefin polymerization catalysis are considered. X-Ray structural data for compounds 1, 3, 4, 5, 8, 9 and 16 are reported.