| Abstract
| - The reaction of the chlorosilyl-substituted cyclopentadienyltitanium compound [Ti(η5-C5H4SiMe2Cl)Cl3] with N,N‘-dimethylethylenediamine in the presence of 2 equiv of NEt3 gave amixture of two complexes, [Ti{η5-C5H4SiMe2NMe(CH2)2-η-NMe}Cl2] (1) and [Ti{η5-C5H4SiMe2-η-N(CH2)2-η-NHMe}Cl2] (2), in a molar ratio of 3:1. However, a similar reaction withN-methylethylenediamine afforded complex 2 regiospecifically. The dialkyl derivatives [Ti{η5-C5H4SiMe2NMe(CH2)2-η-NMe}R2] (R = Me (3), CH2Ph (4)) were prepared by reactingthe dichloride complex 1 with 2 equiv of MgClMe or 1 equiv of Mg(CH2Ph)2·2THF,respectively. The analogous reaction with LiNMe2 afforded the diamido derivative [Ti{η5-C5H4SiMe2NMe(CH2)2-η-NMe}(NMe2)2] (5) in high yield. Complex 1 reacts with dry CO2 viainsertion of a molecule of CO2 into each of the Ti−N and Si−N bonds to yield the dicarbamatecompound [Ti{(η5-C5H4SiMe2OC(O)NMe(CH2)2NMe(η2-CO2)}Cl2] (6), in which the carbamategroups are bound in η2- and η1-fashion. Thermal decomposition of complex 6 afforded theknown oxo derivatives [Ti{μ-(η5-C5H4SiMe2-η-O)}Cl2]2 and [(TiCl2)2(μ-O)-[μ-{(η5-C5H4SiMe2)2(μ-O)}] with elimination of CO2 and 1,3-dimethyl-2-imidazolidinone. The conformationalinterconversion of 1 and 6 and the reversible coordination of the terminal “NHMe” group tothe metal center in 2 were studied in solution by DNMR spectroscopy. The crystal structureof 1 was determined by X-ray diffraction methods.
- Linked Cp−amido derivatives of titanium are synthesized by reaction of diamines with [Ti(η5-C5H4SiMe2Cl)Cl3] in the presence of a base, the final compound depending on the nature of the diamine, which reacts with CO2 to afford the dicarbamate complexes. Dynamic processes studied by DNMR spectroscopy and crystal structure diffraction studies are reported.
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