The first early transition metal perfluorovinyl complexes: the synthesis of Cp_2M(CF=CF_2)_nX_(2-n) (Cp: #eta#~5-C_5H_5~-; M = Ti, Zr; X = Cl or F) and structures of Cp_2Ti(CF=CF_2)_nX_(2-n) (X = Cl, F) via Ti K-edge EXAFS studies

摘要

A new route to perfluorovinyl compounds, recently reported by us, has been used to prepare the first examples of early transition metal complexes of the type Cp_2M(CF=CF_2)_nX_(n-2) (Cp: #eta#~5-C_5H_5~-; M = Ti, Zr; X = Cl or F). These compounds are obtained in high yield from the two-stage, one-pot, reaction of HFC-134a (CF_3CH_2F) with two equivalents of BuLi, followed by addition of Cp_2MX_2 (M = Ti, Zr, X = F, Cl). For two of the titanium-containing compounds Ti K-edge EXAFS data have been recorded from which distances for the titanium-carbon bond of the perfluorovinyl group of 2.033(12) and 2.050(18) A in Cp_2Ti(CF=CF_2)_2 and Cp_2Ti(CF=CF_2)F are obtained. This is the first report of structural data for any perfluorovinyl organometallic compound, and the distances obtained are consistent with the perfluorovinyl group binding in a simple sigma fashion.