ansa-Cyclopentadienyl-Phenoxy Titanium(IV) Complexes (PHENICS): Synthesis, Characterization, and Catalytic Behavior in Olefin Polymerization

作者：Nabika Masaaki; Katayama Hiroaki; Watanabe Tsuyoshi; Kawamura Kuribayashi Hiroshi; Yanagi Kazunori; Imai Akio^*

来源：Organometallics, 2009, 28(13): 3785-3792.

DOI：10.1021/om900019q

A series of ansa-cyclopentadienyl-phenoxy titanium complexes (PHENICS: phenoxy-induced complex of Sumitomo) (1a-e), [{Me(2)CCp(OC(6)H(2)-3-R-5-R')}TiCl(2)] (1a, R = R' = H; 1b, R = (t)Bu, R' = Me) and [{Me(2)Si(C(5)Me(4))(OC(6)H(2)-3-R ''-5-Me)}TiCl(2)] (1c, R '' = (i)Pr; 1d, R '' = (t)Bu; 1e, R '' = Adm), have been synthesized and characterized. It is noteworthy that the dihedral angles of the cyclopentadienyl and phenoxy moieties of the complexes 1b and Id. revealed by X-ray crystal structure analysis, are 63.0 degrees (1b) and 68.2 degrees (1d), indicating a distortion from a Mutual perpendicular arrangement, whereas the symmetrical patterns of the (1)H NMR spectra indicate a dynamic behavior in solution. The PHENICS-type complexes exhibit good to excel lent catalytic activities for copolymerization of ethylene and 1-hexeric upon activation with Al(t)Bu(3)/[Ph(3)C][B(C(6)F(5))(4)] cocatalyst. Particularly, the complexes with a bulky substituent, at the ortho position of the phenoxy moiety showed excellent catalytic features (1d 27 200 kg mol(-1) h(-1) at 80 degrees C, 6000 kg mol(-1) h(-1) at 180 degrees C). These data show that the catalytic activity of the PHENICS-type catalysts is higher than that reported for the so-called constrained geometry catalyst (CGC) precursors. This becomes even more evident in light of the results for polymerization at 180 degrees C. Whereas the PHENICS catalyst system acts as a single-site catalyst at 180 degrees C, the CGC-type catalysts proved to be inactive under analogous conditions. Moreover, the copolymers obtained with PHENICS incorporate much higher content of 1-hexene than those obtained with CGC.

• 出版日期2009-7-13