Synthesis, structure and ethylene polymerization behavior of titanium phosphinoamide complexes

Abstract

(Phosphinoamide)(cyclopentadienyl)titanium(IV) complexes of the type Cp*TiCl 2(η 2-Ph 2PNR) [Cp*=C 5Me 5; R = t-Bu ( 2a), R = n-Bu ( 2b), R = Ph ( 2c)] have been prepared by the reaction of Cp*TiCl 3 with the corresponding lithium phosphinoamides. The structure of Cp*TiCl 2(η 2-Ph 2PN t Bu) ( 2a) and Cp*TiCl 2(η 2-Ph 2PNPh) ( 2c) have been determined by X-ray crystallography. These complexes exhibited moderate catalytic activities for ethylene polymerization in the presence of modified methylaluminoxane (MMAO). Catalytic activity of up to 2.5 × 10 6 g/(mol Ti h) was observed when activated by i-Bu 3Al/Ph 3CB(C 6F 5) 4.