Crystal structure of di­aqua­bis­­(4-tert-butyl­benzoato-κO)bis­­(nicotinamide-κN1)cobalt(II) dihydrate

The asymmetric unit of the mononuclear cobalt complex, [Co(C11H13O2)2(C6H6N2O)2(H2O)2]·2H2O, contains one half of the complex mol­ecule, one coordinating and one non-coordinating water mol­ecule, one 4-tert-butyl­benzoate (TBB) ligand and one nicotinamide (NA) ligand; the Co atom lies on an inversion centre. All ligands coordinating to the Co atom are monodentate. The four nearest O atoms around the Co atom form a slightly distorted square-planar arrangement, with the distorted octa­hedral coordination completed by the two pyridine N atoms of the NA ligands at distances of 2.1638 (11) Å. The coordinating water mol­ecules are hydrogen bonded to the carboxyl O atoms [O ⋯ O = 2.6230 (17) Å], enclosing an S(6) hydrogen-bonding motif, while inter­molecular O—H⋯O hydrogen bonds link two of the non-coordinating water mol­ecules to the coordinating water mol­ecules and NA anions. The dihedral angle between the planar carboxyl­ate group and the adjacent benzene ring is 29.09 (10)°, while the benzene and pyridine rings are oriented at a dihedral angle of 88.53 (4)°. In the crystal, O—H⋯O and N—H⋯O hydrogen bonds link the mol­ecules, enclosing R22(8), R22(10) and R44(12) ring motifs, forming layers parallel to (001). The C and H atoms of the tert-butyl group of the TBB ligand are disordered over two sets of sites with an occupancy ratio of 0.631 (5):0.369 (5).