Cp,Cp*-Dimethyltantalum Triflate

Abstract

(η^5-Cyclopentadienyl)(dimethyl)(η^5-pentamethylcyclopentadienyl)tantalum trifluoromethylsulfonate, [Ta(C_5H_5)(C_(10)H_(15)CH_3)_2]CF_3S0_3, M_r = 560.41, orthorhombic, Pbca, ɑ = 14.230 (4), b = 19.283 (4), c = 14.628 (4) Å, v = 4014 (2) Å^3, z = 8, D_x = 1.855 g cm^(-3), λ(Mo Kɑ)= 0.71073 Å, μ = 55.3 cm^(-1), F(000) = 2192, room temperature, R(F) = 0.038 for 1882 reflections with F_o^2 > 3σ(F_o^2). The Ta-C(methyl)Å distances are virtually equal at 2.171 (12) Å, with a C-Ta-C angle of 95.8 (5)º. The coordination of the two η^5 ligands is normal; the Cp(centroid}-Ta-Cp^*(centroid) angle is 136.2°. Intermolecular contacts are all approximately at van der Waals distances, with indications of CH···O hydrogen bonding between methyl groups and the triflate anion.