159771-60-5Relevant academic research and scientific papers
New silyl-substituted cyclopentadienyl titanium and zirconium complexes. X-ray molecular structures of [TiCl2{μ-(OSiMe2-η5-C5H 4)}]2 and [ZrCl2{μ-[(η5-C5H4)SiMe 2OSiMe2(η5-C5H4)]}]
Ciruelos, Santiago,Cuenca, Tomás,Gómez-Sal, Pilar,Manzanero, Antonio,Royo, Pascual
, p. 177 - 185 (2008/10/08)
We report the synthesis of 1-(chlorodimethylsilyl)-1-(trimethylsilyl)cyclopentadiene, 1. The reaction of a toluene solution of 1 with one equivalent of MCl4 (M = Ti, Zr) leads to the mono(cyclopentadienyl) derivatives [MCl3(η5-C5H4SiMe 2Cl)] [M = Ti (2); M = Zr (3)] in 76 and 87% yields, respectively. The same reaction with ZrCl4 in a Zr/Cp molar ratio 1:2 in refluxing methylene dichloride yields the dicyclopentadienyl derivative [ZrCl2(η5-C5H4SiMe 2Cl)2], 4, whereas the related titanium compound cannot be synthesized by this method. These mono- and bis(cyclopentadienyl) complexes are very moisture sensitive and react with water to give different oxo complexes. Reaction of one equivalent of water with [TiCl3(η5-C5H4SiMe 2Cl)] in toluene takes place with elimination of HCl, resulting in formation of the dinuclear titanium methylsiloxane derivative [TiCl2{μ-(OSiMe2-η5-C5H 4)}]2, 5, in a quantitative yield, which by further addition of one equivalent of water gives the mononuclear compound [TiCl2{OSiMe2OSiMe2(η5-C 5H4)}], 6, in very low yield. However the best procedure to obtain 6 (in 45% yield) is the direct reaction of [TiCl3(η5-C5H4SiMe 2Cl)] with two equivalents of water. The analogous reaction of [ZrCl2(η5-C5H4SiMe 2Cl)2] with one equivalent of water proceeds to give [ZrCl2{μ[(η5-C5H4)SiMe 2OSiMe2(η5-C5H4)]}], 7. Alkylation of [TiCl3(η5-C5H4SiMe 2Cl)] with Mg(CH2C6H5)2(THF)2 leads to the tribenzyl derivative [Ti(CH2C6H5)3(η 5-C5H4SiMe2Cl)], 8, and alkylation of [TiCl2{μ-(OSiMe2-η5-C5H 4)}]2 with MgClMe and Mg(CH2C6H5)2(THF)2 allows the isolation of the oxoalkyl complexes [TiR2{μ-(OSiMe2-η5-C5H 4)}]2 [R = Me, 9; R = CH2C6H5, 10]. Reaction of [MCl3(η5-C5H4SiMe 2Cl)] with LiN(SiMe3)2 gives the amido complex [TiCl2{N(SiMe3)2(η5-C 5H4SiMe2Cl)}], 11, whereas a similar reaction with LiNHtBu takes place with simultaneous elimination of HCl to give the cyclic amido pendant cyclopentadienyl complex [TiCl2{NtBuSiMe2(η5-C 5H4)}], 12. The molecular structures of [TiCl2{μ-(OSiMe2-η5-C5H 4)}]2 and [ZrCl2{μ-[(η5-C5H4)SiMe 2OSiMe2(η5-C5H4)]}] have been determined by X-ray diffraction methods. Complex 5 is a dimer formed by two [Me2-SiCpTiCl2] fragments bonded by two oxygen bridges, connecting the silicon and titanium atoms from different units. 5 crystallizes in monoclinic space group P21/n with a = 9.461-(7), b = 10.926(1), c = 10.507(3) A?, β = 95.20(2)°, and V = 1081(1) A?3 for Z = 2. The molecular structure of 7 corresponds to a typical bent dicyclopentadienyl system. Complex 7 crystallizes in the space group P21/c with a = 13.479(4), b = 8.654(1), c = 15.343(5) A?, β = 97.18(2)°, and V = 1775(2) A?3 for Z = 4.
