Synthesis and structure of titanium diolate complexes derived from CpTiCl3

Abstract

The compounds [Cl2CpTi]2(OCH2CH2CH2O) 1, [Cl2CpTi]2(OCH2CMe2CH2O) 2, and [Cl2CpTi]2-(OCHMeCH2CHMeO) 3 were prepared from the reactions of CpTiCl3 and the bis-trimethylsilyl ethers of the diols. Alternatively, these species could be made from the reactions of the diol, imidazole, and CpTiCl3 employing the appropriate stoichiometry. In the presence of excess diol, loss of CpH is observed. In the case of 1,3-propanediol the species [TiCl(HOCH2CH2CH2O)(OCH2CH2CH2O)]24 was isolated. Recrystallization of 4 from THF led to the isolation of [TiCl2(OCH2CH2CH2O)(THF)]25, albeit in very low yield. This chemistry is described and the implications are considered. Compounds 1, 3, 4, and 5 were characterized crystallographically; the parameters are summarized as follows: 1: C2/c (No. 15), a = 12.587(2) Å, b = 9.632(2) Å, c = 15.824(3) Å, β = 107.88(1)°, V = 1811.3(5) Å3, Z = 4; 3: C2/c (No. 15), a = 12.855(2) Å, b = 10.772(2) Å, c = 15.665(2) Å, β = 109.26(1)°, V = 2047.7(5) Å3, Z = 4; 4: P21/n (No. 14), a = 8.911(3) Å, b = 7.821(2) Å, c = 13.986(2) Å, β = 102.56(2)°, V = 951.3(3) Å3, Z = 2; 5: P21/n (No. 14), a = 8.693(3) Å, b = 9.286(2) Å, c = 13.411(2) Å, β = 101.18(2)°, V = 1062.1(4) Å3, Z = 2. Keywords: titanium alkoxides, structure, synthesis.