(2-Amino-7-methyl-4-oxidopteridine-6-carboxylato-kappa O-3(4),N-5,O-6)(ethane-1,2-diamine-kappa N-2,N')(1H-imidazole-kappa N-3)-nickel(II) dihydrate

In the title complex, [Ni(C8H5N5O3)(C2H8N2)(C3N2H4)]center dot-2H(2)O, a tridentate 2-amino-7-methyl-4-oxidopteridine-6-carboxylate (pterin) ligand, a bidentate ancillary ethane-1,2-diamine(en) ligand and a monodentate 1H-imidazole (im) ligand complete a distorted octahedral geometry around the Ni-II atom. The pterin ligand forms two chelate rings. Both the en and im ligands are arranged nearly orthogonally relative to the pterin ligand [dihedral angles between the mean planes of the en and pterin ligands and of the im and pterin ligands are 84.62 (9) and 85.14 (9)degrees, respectively]. N-H center dot center dot center dot N, N-H center dot center dot center dot O, O-H center dot center dot center dot N and O-H center dot center dot center dot O hydrogen bonds link the complex molecules and lattice water molecules into a three-dimensional network.