Investigations of the vanadium–oxo–organophosphonato system: preparation and structural characterization of a mixed-valence VV–VIV cluster encapsulating chloride anions, (Bu4N)2[(V8O16){V4O4(H2O)12}(PhPO3)8Cl2]·2Et2O·2MeOH·4H2O

Abstract

The reaction of (Bu₄N)[V₅O₇(OMe)₂(PhPO₃)₅] with aqueous HCl in methanol followed by treatment with diethyl ether yields dark brown crystals of (Bu₄N)₂[(V₈O₁₆){V₄O₄(H₂O)₁₂}(PhPO₃)₈Cl₂]·2Et₂O·2MeOH·4H₂O 1, a mixed-valence V^V–V^IV cluster consisting of two (V₄O₈)⁴⁺ caps each bridged through four PhPO₃^2– groups to a central girdle of four [VO(H₂O)₃]²⁺ units, and encapsulating two chloride anions in the molecular cavity.