Synthesis, spectral and structural characterization of vanadium lactate, malate and citrate with large counter cation

Vanadium lactate, malate and citrate [Ni(phen)3]2[VV2O4(lact)2]Cl2·20H2O·2EtOH (1), [Ni(phen)3][VIVO(mal)(phen)]Cl·14H2O (2) and [Ni(phen)3]2[VIV2O2(Hcit)(cit)]Cl·17H2O (3) (H2lact = lactic acid, H3mal = malic acid, H4cit = citric acid, and phen = 1,10-phenanthroline) have been obtained with large counter cation [Ni(phen)3]2+. In mononuclear complex 2, vanadium atom exists in a distorted octahedral environment. The distance of V–O bond (α-alkoxy) in 2 is significantly shorter than V–O bond (α-hydroxy) in [VO(Hmal)(bpy)]·H2O and [VO(Hcit)(phen)]2·6.5H2O [1] reported, which is attributed to the deprotonation of α-alkoxy group in 2. The anions of 1 and 3 have VV2O4 and VIV2O2 diagonal structures respectively and have two bridging oxygen atoms from the alkoxy groups of α-hydroxycarboxylates. The vanadium atoms in 1 and 3 are penta-coordinated, except V1 in 3 is hexa-coordinated. The different coordination modes of carboxy group result in different V–O (α-carboxy) distances.