| Abstract: | Synthesis of a Titana-Oxacyclohexane Ring by Controlled Ring Opening of Tetrahydrofurane. Crystal Structures of [Ti(CH2)4O{Me2Si(NBut)2}]2, [TiCl{Me2Si(NBut)2}]3(μ3-O)(μ3-Cl), and [Li2(THF)3{Me2Si(NBut)2}] [TiCl3(THF)3] reacts with [(ButNLi)2SiMe2]2 in diethyl ether at –35 °C under redox disproportionation and formation of the yellow titana(IV)-oxacyclohexane complex [Ti(CH2)4O{Me2Si(NBut)2}]2. According to the crystal structure analysis the titanium atoms are linked to form centrosymmetric dimers via the oxygen atoms of the Ti(CH2)4O six-membered rings, which are in chair conformation. Along with the nitrogen atoms of the chelating [Me2Si(NBut)2]2– ligands the titanium atoms obtain a distorted trigonal-bipyramidal surrounding. While [TiCl{Me2Si(NBut)2}]3(μ3-O)(μ3-Cl) with a cluster-like structure is obtained as a by-product. According to the crystal structure analysis of [Li2(THF)3 · {Me2Si(NBut)2}], which is involved in the synthesis reaction, the two lithium atoms are connected with both the nitrogen atoms of the t-butyl amide groups and bridged via an oxygen atom of one of the THF molecules. |
