Monocyclopentadienylchlorooxotitanium(IV) dimers, trimers and tetramers

Abstract

High-yield syntheses (90%) of the monocyclopentadienyloxochloro complexes [(TiLCl₂)₂(µ-O)]2, [(TiLCl)₄(µ-O)₄]3, [(TiL)₄(µ-O)₆]4 and [(TiLCl)₃(µ-O)₃]5 have been achieved by hydrolysis of the precursors [TiLCl₃]1[L =η⁵-C₅H₅, C₅H₄Me, C₅H₄(SiMe₃) or C₅Me₅]. In addition [Ti{η⁵-C₅H₄(SiMe₃)}Br₃]7, [Ti₄{η⁵-C₅H₄(SiMe₃)}₄Br₄(µ-O)₄]8 and [Ti₄{η⁵-C₅H₄(SiMe₃)}₄(NCS)₄(µ-O)₄]9 have been prepared. The structures of the cyclic trimer 5(L =η⁵-C₅Me₅) and tetramer 9 have been determined by X-ray analysis: 5, monoclinic, space group P2₁/c, a= 16.724(2), b= 8.958(1), c= 22.871(2)Å, β= 91.73(1)°, Z= 4 and R= 0.065 for 3159 independent observed reflections; 9, monoclinic, space group Cc, a= 24.527(2), b= 12.520(2), c= 18.931(2)Å, β= 115.46(2)°, Z= 4 and R= 0.060 for 3088 independent observed reflections. The electronic configurations of complexes 2–5 have been calculated by extended-Hückel molecular orbital calculations.