Diaqua-bis[4-(dimethyl-amino)-benzoato]-κO,O';κO-(isonicotinamide-κN)cobalt(II).

The title Co(II) complex, [Co(C(9)H(10)NO(2))(2)(C(6)H(6)N(2)O)(H(2)O)(2)], contains two 4-dimethyl-amino-benzoate (DMAB) anions, one isonicotinamide (INA) ligand and two coordinated water mol-ecules. One of the DMAB anions acts as a bidentate ligand, while the other is monodentate. The four O atoms in the equatorial plane around the Co atom form a highly distorted square-planar arrangement, while the distorted octa-hedral coordination geometry is completed by the N atom of the INA ligand and the O atom of the second water mol-ecule in the axial positions. An intra-molecular O-H⋯O hydrogen bond between the monodentate-coordinated carboxyl group and a coordinated water mol-ecule results in a six-membered ring with an envelope conformation. The dihedral angles between the carboxyl groups and the adjacent benzene rings are 4.29 (10)° for the monodentate ligand and 2.31 (13)° for the bidentate ligand, while the two benzene rings are oriented at a dihedral angle of 65.02 (5)°. The dihedral angles between the pyridine and benzene rings are 11.21 (5)° for the monodentate ligand and 74.60 (5)° for the bidentate ligand. In the crystal structure, inter-molecular O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds link the mol-ecules into a supra-molecular structure.