The first early transition metal perfluorovinyl complexes: the synthesis of Cp2M(CF=CF2)(n)X2-n (Cp : eta(5)-C5H5-; M = Ti, Zr; X = Cl or F) and structures of Cp2Ti(CF=CF2)(n)X2-n (X = Cl, F) via TiK-edge EXAFS studies

A new route to perfluorovinyl compounds, recently reported by us, has been used to prepare the first examples of early transition metal complexes of t he type Cp2M(CF=CF2)(n)Xn - 2 (Cp: eta(5)-C5H5-; M = Ti, Zr; X = Cl or F). These compounds are obtained in high yield from the two-stage, one-pot, rea ction of HFC-134a (CF3CH2F) with two equivalents of BuLi, followed by addit ion of Cp2MX2 (M = Ti, Zr, X = F, Cl). For two of the titanium-containing c ompounds Ti K-edge EXAFS data have been recorded from which distances for t he titanium-carbon bond of the perfluorovinyl group of 2.033(12) and 2.050( 18) Angstrom in Cp2Ti(CF=CF2)(2) and Cp2Ti(CF=CF2)F are obtained. This is t he first report of structural data for any perfluorovinyl organometallic co mpound, and the distances obtained are consistent with the perfluorovinyl g roup binding in a simple sigma fashion. (C) 1999 Elsevier Science S.A. All rights reserved.