Synthesis, structure, and reactivity of the phosphinimide complexes (t-Bu3PN)nMa4-n (M = Ti, Zr)

The phosphinimide complexes (t-Bu3PN)TiCl3 (1) and (t-Bu3PN)(2)TiCl2 (4) are readily prepared in high yields from the stoichiometric reaction of t-Bu3PNSiMe3 and TiCl4, while (t-Bu3PN)(3)TiCl (11) is readily obtained from the reaction of t-Bu3PNLi and TiCl4. The analogous 1:1 or 2:1 reactions of ZrCl4 and t-Bu3PNLi afford mixtures of products, although in the 3:1 stoichiometric ratio (t-Bu3PN)(3)ZrCl (12) is isolable. These complexes are readily alkylated with a variety of reagents to give (t-Bu3PN)TiMe3 (2), (t-Bu3PN)Ti(CH2Ph)(3) (3), (t-Bu3PN)(2)TiMe2 (5), (t Bu3PN)(2)Ti(eta(3)-C3H5)(2) (6), (t-Bu3PN)(2)Ti(CH2Ph)(2) (7), (t-Bu3PN)(2)TiPh2 (8), (t-Bu3PN)(2)Ti(eta(5)-Cp)Cl (9), (t-B3PN)(2)Ti(eta(5)-CP)Me (10), (t-Bu3PN)(3)TiMe (13), (t-Bu3PN)(3)TiPh (14), (t-Bu3PN)(3)ZrMe (15), (t-Bu3PN)(3)Zr(CH2Ph) (16), and (t-Bu3PN)(3)Zr(eta(5)-Cp) (17). Subsequent reactions of some of these alkyl derivatives with [PhNMe2H][B(C6F5)(4)], [Ph3C]-[B(C6F5)(4)], Or B(C6F5)3 are investigated. A number of zwitterionic and cationic species complexes have been characterized. These include [(t-Bu3PN)Ti(CH2Ph)(2)( PhCH2)B(C6F5)(3)] (18), [(t- Bu3PN)(2)TiMe(PMe3)] [B(C6F5)(4)] (19), (t-Bu3PN)(2)TiMe (mu-MeB(C6F5)(3)) (20), (t-Bu-3-PN)(2)Ti(mu-MeB(C6F5)(3))(2) (21), and (t-Bu3PN)(2)Ti(C6F5)(2) (22). The implications of this chemistry are considered. Structural data for 1, 4, 5, 12, 18, 21, and 22 are described.