X-ray structure, solution properties, and biological activity profile of vanadocene(IV) acetylacetonate complex, [VCp₂(acac)](CF₃SO₃): A dual-function anti-cancer agent with anti-angiogenic and anti-mitotic properties

The structure of [V(η⁵-C₅H₅)₂(CH ₃C(O)CHC(O)CH₃)](O₃SCF₃) (1) (=[VCp₂(acac)](O₃SCF₃)), a dual-function anti-cancer agent with anti-angiogenic and anti-mitotic properties, was determined by single-crystal X-ray diffraction. The geometry is well described as a pseudo-tetrahedral like structure with the centroids of the cyclopentadienyl rings and the two oxygen atoms of the acetylacetonate ring in the ancillary positions of the central vanadium (IV) atom. The bisector of the V(acac) fragment deviates from the C₂ axis of the ligand framework by only 4°, compared to a deviation of 7° for the V(acac) fragment in the tetramethylethano-bridged vanadocene acetyl acetonate complex. Crystal data for 1: space group, P2₁/c; a = 7.5544(9) Å, b = 14.936(2) Å, c = 16.193(2) Å, β = 102.901(2)°, V = 1781.0(4) ų; Z = 4; R = 0.0506 for 2310 reflections with I > 2σ(I). This report also details the electron paramagnetic resonance, UV/Vis spectroscopy, electrochemical properties and the biological activity profile of this potent anti-cancer agent.