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

The title compound, aqua[bis(salicylidene)ethylenediaminato-O,N,N',O']oxovanadium(V) nitrate, [VO(C(16)H(14)N(2)O(2))(H(2)O)]NO(3), 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 V--O(water) bond trans to V==O. The coordinated water molecules are hydrogen bonded to the nitrate 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) A, respectively, in the triclinic form, and 1.588 (3) and 2.230 (3) A, respectively, in the monoclinic form. In the triclinic form, the dimers pack so that the salen [bis(salicylidene)ethylenediaminate] ligands are parallel to each other, whereas in the monoclinic form, which is the denser, there is a herring-bone arrangement.