Cis- and trans-titanium complexes with doubly silyl-bridged dicyclopentadienyl ligands: molecular structure of [(TiCl)2 (μ-0) {(SiMe2)2(η5-C5H3)2}]2 (μ-O)2

Abstract

The reaction of TiCl4 with Li2[(SiMe2)2(η5-C5H3)2] in toluene at room temperature afforded a mixture of cis- and trans-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] in a molar ratio of Full-size image (<1 K) after recrystallization. The complex trans-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] was hydrolyzed immediately by the addition of water to THF solutions to give trans-[(TiCl2)2(μ-O){(SiMe2)2(η5-C5H3)2}] as a solid insoluble in all organic solvents, whereas hydrolysis of cis-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] under different conditions led to the dinuclear μ-oxo complex cis-[(TiCl2)2)(μ-O){(SiMe2)2(η5-C5H3)2}] and two oxo complexes of the same stoichiometry [(TiCl)2(μ-O){(SiMe2)2(η5-C5H3)2}]2(μ-O)2 as crystalline solids. Alkylation of cis- and trans-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] with MgCIMe led respectively to the partially alkylated cis-[(TiMe2Cl)2{(SiMe2)2(η5-C5H3)2}] and the totally alkylated trans-[(TiMe3)2{(SiMe2)2(η5-C5H3)2}] compounds. The crystal and molecular structure of the tetranuclear oxo complex [(TiCl)2(μ-O){(SiMe2)2(η5-C5H3)2}]2(μ-O)2 was determined by X-ray diffraction.