trans-Bis[4-amino-3,5-bis(2-pyridyl)-4H-1,2,4-triazole-κN3]diaquacobalt(II) bis(3-carboxy-5-nitrobenzoate)

The title complex, [Co(C12H10N6)(2)(H2O)(2)](C8H4NO6)(2), is composed of a mononuclear cobalt(II) cation and two 3-carboxy-5-nitrobenzoate anions for charge balance. In the cation, the Co-II atom is six-coordinated in a distorted octahedral geometry. It bonds to two O atoms of two water molecules, and two pairs of N atoms from two 4-amino-3,5-bis(2-pyridyl)-4H-1,2,4-triazole molecules, which behave as bidentate chelating ligands. There are intramolecular N-H center dot center dot center dot N hydrogen bonds in the cation. In the crystal, there are a number of intermolecular N-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds, as well as intermolecular pi-pi stacking interactions [centroid-centroid distances = 3.657 (2) and 3.847 (2) angstrom], that link the molecules into two-dimensional networks lying parallel to the ab plane. The presence of C-H center dot center dot center dot O interactions leads to the formation of a three-dimensional network.