In Search for Titanocene Complexes with Improved Cytotoxic Activity: Synthesis, X-Ray Structure, and Spectroscopic Study of Bis(η (5)-cyclopentadienyl)difluorotitanium(IV)

The 1 : 2 reaction of [Ti(η (5)-C(5)H(5))(2)Cl(2)] and AgF in CHCl(3)/H(2)O yielded the fluoro analog [Ti(η (5)-C(5)H(5))(2)F(2)] (1) in almost quantitative yield (C(5)H(5) is the cyclopentadienyl group). The coordination about the Ti(IV) atom formed by two fluoro ligands and the centroids of the cyclopentadienyl rings is distorted tetrahedral. The compound crystallizes in the orthorhombic space group C2cm. The lattice constants are a = 5.9055(4), b = 10.3021(5), c = 14.2619(9) Å, and α = β = γ = 90°. The complex has been characterized by elemental analyses and spectroscopic (IR, (1)H NMR) data. A structural comparison of the four members of the [Ti(η (5)-C(5)H(5))(2)X(2)] family of complexes (X = F, Cl, Br, I) is attempted.