Two polymorphs of aqua[N,N '-ethyl-enebis(salicylideneaminato-N,O)]-oxovanadium(V) nitrate

The title compound, aqua[bis(salicylidene)ethylenediaminato-O,N,N',O']oxova nadium(V) nitrate, [VO(C16H14N2O2)(H2O)]NO3, crystallizes as two polymorphs in the triclinic and monoclinic crystal systems. In both, the V atom has a distorted octahedral coordination geometry with a long VD O-water bond tra ns to V=O. The coordinated water molecules are hydrogen bonded to the nitra te ions so that pairs of cations are linked to give neutral centrosymmetric dimers. The V=O and V-O-water distances are 1.598 (2) and 2.257 (2) Angstr om, respectively, in the triclinic form, and 1.588 (3) and 2.230 (3) Angstr om, respectively, in the monoclinic form. In the triclinic form, the dimers pack so that the salen [bis(salicylidene)ethylenediaminate] ligands are pa rallel to each other, whereas in the monoclinic form, which is the denser, there is a herring-bone arrangement.