Experimental

R factor = 0.030; wR factor = 0.077; data-to-parameter ratio = 12.6. The reaction of Co(NO3)23H2O with pyridine-2,6-dicar-boxylic acid and 3,5-dimethyl-1H-pyrazole in a 1:1:3 molar ratio affords the title complex, [Co(C7H3NO4)(C5H8N2)3]-H2O. The Co II atom is coordinated by one pyridine-2,6-dicarboxylate chelating ligand and three 3,5-dimethyl-1H-pyrazole ligands in a distorted octahedral geometry. Hydrogen-bonding interactions involving the coordinated carboxylate group, 3,5-dimethyl-1H-pyrazole and water help to consolidate the crystal structure Related literature For the use of complexes with pyrazole-based ligands in studying the relationship between the structure and the activity of the active site of metalloproteins, see: Haanstra et al. (1990). For the coordination modes of pyrazole complexes, see: Grotjahn et al. (2003)