Metallocene analogues containing bulky heteroallylic ligands and their use as new olefin polymerization catalysts

TY - JOUR

T1 - Metallocene analogues containing bulky heteroallylic ligands and their use as new olefin polymerization catalysts

AU - Richter, Joachim

AU - Edelmann, Frank T.

AU - Noltemeyer, Mathias

AU - Schmidt, Hans Georg

AU - Shmulinson, Michal

AU - Eisen, Moris S.

N1 - Funding Information: This research was supported by the Ministry of Sciences and Arts, Ministry of Niedersachsen, Germany and the Technion, by the Israel Science Foundation administered by the Israel Academy of Sciences and Humanities under Contract 76/94-1, and by the V.P.R. Fund Promotion of Sponsored Research.

PY - 1998/3/12

Y1 - 1998/3/12

N2 - A series of Ti and Zr metallocene analogues containing bulky benzamidinate ligands has been prepared and fully characterized. Treatment of TiCl4(THF)2 or ZrCl4(THF)2 with two equivalents of the appropriate benzamidinate anions affords the bis(benzamidinato) complexes [C6H5C(NC3H7)2]2MCl2 (M=Ti (1), Zr (2)) and [C6H5C(NC6H11)2]2MCl2 (M = Ti (3), Zr (4)). The zirconium complex 2 was structurally characterized by X-ray diffraction. In a similar manner the nonafluoromesityl derivative [(CF3)3C6H2C(NC6H11)2]2ZrCl2 (5) was synthesized from ZrCl4(THF)2 and Li[(CF3)3C6H2C(NC6H11)2]. Methylation of 4 with methyllithium yields the dimethyl complex [C6H5C(NC6H11)2]2ZrMe2 (6). The mixed-ligand metallocene analogues [C6H5C(NC3HT7)2](C5Me5)MCl2 (M = Ti (7), Zr (8)) and [C6H5C(NC6H11)2](C5Me5)TiCl2 (9) have been prepared by reacting (C5Me5)TiCl3 or (Cs5Me5)ZrCl3 with one equivalent of a lithium N,N'-dialkytbenzamidinate. The polymerization of ethylene and propylene has been studied by the catalytic precatalyst complexes I and 2 upon reaction of an excess of methylalumoxane to obtain the active cationic complexes. The polymerization activity of the complexes is comparable to other benzamidinate ancillary containing ligands although toward shorter amounts of time due to a competitive inhibition presumably obtained by a β-hydrogen elimination from the ligand. Polymerization activity is strongly dependent on catalyst and cocatalyst concentrations and on temperature.

AB - A series of Ti and Zr metallocene analogues containing bulky benzamidinate ligands has been prepared and fully characterized. Treatment of TiCl4(THF)2 or ZrCl4(THF)2 with two equivalents of the appropriate benzamidinate anions affords the bis(benzamidinato) complexes [C6H5C(NC3H7)2]2MCl2 (M=Ti (1), Zr (2)) and [C6H5C(NC6H11)2]2MCl2 (M = Ti (3), Zr (4)). The zirconium complex 2 was structurally characterized by X-ray diffraction. In a similar manner the nonafluoromesityl derivative [(CF3)3C6H2C(NC6H11)2]2ZrCl2 (5) was synthesized from ZrCl4(THF)2 and Li[(CF3)3C6H2C(NC6H11)2]. Methylation of 4 with methyllithium yields the dimethyl complex [C6H5C(NC6H11)2]2ZrMe2 (6). The mixed-ligand metallocene analogues [C6H5C(NC3HT7)2](C5Me5)MCl2 (M = Ti (7), Zr (8)) and [C6H5C(NC6H11)2](C5Me5)TiCl2 (9) have been prepared by reacting (C5Me5)TiCl3 or (Cs5Me5)ZrCl3 with one equivalent of a lithium N,N'-dialkytbenzamidinate. The polymerization of ethylene and propylene has been studied by the catalytic precatalyst complexes I and 2 upon reaction of an excess of methylalumoxane to obtain the active cationic complexes. The polymerization activity of the complexes is comparable to other benzamidinate ancillary containing ligands although toward shorter amounts of time due to a competitive inhibition presumably obtained by a β-hydrogen elimination from the ligand. Polymerization activity is strongly dependent on catalyst and cocatalyst concentrations and on temperature.

KW - Heteroallylic ligands

KW - Metallocene analogues

KW - Olefin polymerization

KW - Zirconium complexes

UR - http://www.scopus.com/inward/record.url?scp=0032510470&partnerID=8YFLogxK

U2 - 10.1016/S1381-1169(97)00209-4

DO - 10.1016/S1381-1169(97)00209-4

M3 - 文章

AN - SCOPUS:0032510470

SN - 1381-1169

VL - 130

SP - 149

EP - 162

JO - Journal of Molecular Catalysis A: Chemical

JF - Journal of Molecular Catalysis A: Chemical

IS - 1-2

ER -