Two compounds containing a divanadium tetrabenzoate frame and cyclopentadienyl or pentamethylcyclopentadienyl ligands

Article abstract of DOI:10.1021/om00126a006

Two compounds (η⁵-C₅H₅)₂V₂(C ₆H₅CO₂)₄, 1, and (η⁵-C₅Me₅)₂V₂(C ₆H₅CO₂)₄, 2, have been prepared from vanadocene and decamethylvanadocene, respectively, and characterized by single-crystal X-ray crystallography. The data are as follows. For 1: P1; a = 10.640 (2) A?, b = 10.774 (3) A?, c = 8.510 (2) A?, α = 112.83 (2)°, β = 101.41 (2)°, γ = 69.43 (2)°, V = 839.6 (6) A?³, Z = 1, R₁ = 0.0477, R₂ = 0.0547. For 2: C2/c; a = 11.576 (3) A?, b = 16.721 (2) A?, c = 21.452 (2) A?, β = 90.45 (3)°, V = 4152 (3) A?³, Z = 4, R₁ = 0.0733, R₂ = 0.0885. The V-V′ distances of 3.636 (1) A? for 1 and 3.652 (2) A? for 2 suggest that little if any direct bonding occurs between two vanadium atoms. The presence of pentamethylcyclopentadienyl ligands in the axial positions in 2 causes a twist of the four carboxylate bridges with torsional angles for the two independent O-V-V′-O′ units equal to 5.9° and 10.9°. In the cyclopentadienyl derivative 1 the corresponding torsional angles are each 2.6°.