Dimeric Structures of Cp'TiCl2 Compounds with Bulky Substituents at the Cyclopentadienyl Rings

Abstract

The complexes [(η5-C5Me4Ph)TiCl(μ-Cl)]2 (1) and [(η5-C5Bn5)TiCl(μ-Cl)]2 (2) (Bn = benzyl) were obtained by the reaction of TiCl3 and the corresponding alkali metal cyclopentadienides in a THF-toluene mixture. The X-ray diffraction single-crystal analysis revealed that both compounds form centrosymmetric dimers bridged via a pair of chloride ligands. Compound 1 crystallizes in the monoclinic space group P21/n (No. 14; a = 11.387(3) Å, b = 16.496(2) Å, c = 8.383(2) Å, β = 110.786(15)°, V = 1 472.2(6) Å3, Z = 2), and compound 2 in the monoclinic space group P21/c (No. 14; a = 18.967(5) Å, b = 10.7190(10) Å, c = 17.996(5) Å, β = 116.747(15)°, V = 3 267.2(13) Å3, Z = 2). Common features of the structures differ only negligibly. The Ti-Ti distance (in 1 3.3345(11) Å, in 2 3.374(2) Å) is considerably shorter than in paramagnetic dimeric titanocene monochlorides (3.91-3.95 Å). The compounds are diamagnetic, probably due to spin-paired d1 electrons.