p-Hydroquinone–metal compounds: synthesis and crystal structure of two novel VV–p-hydroquinonate and VIV–p-semiquinonate species

Reaction of the p-hydroquinone derivative H₂Na₄bicah·4H₂O with either V^IVOSO₄·3H₂O and NaV^VO₃ in equivalent quantities or with NaV^VO₃ yields the tetranuclear V^IVO²⁺ macrocycle–semiquinonate compound Na₆{(V^IVO)₄(μ₂-O)₂[μ₂-bicas·(−5)-N,O,O,O]₂}·Na₂SO₄·20H₂O (1·Na₂SO₄·20H₂O) and the dinuclear cis-V^VO₂⁺–hydroquinone species Na₄{(V^VO₂)₂[μ₂-bicah(−6)-N,O,O,O]}·11H₂O (2·11H₂O) respectively. Compounds 1·Na₂SO₄·20H₂O and 2·11H₂O were characterized by X-ray structure analysis and ab initio calculations.