metal-organic compounds
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The NiII atom in the title complex, [Ni(C8H5N5O3)(C2H8N2)(H2O)]·2H2O, is six-coordinated in a distorted octahedral geometry by a tridentate 2-amino-7-methyl-4-oxidopteridine-6-carboxylate (pterin) ligand, a bidentate ancillary ethane-1,2-diamine (en) ligand and a water molecule. The pterin ligand forms two chelate rings. The en and pterin ligands are arranged nearly orthogonally [dihedral angle between the mean plane of the en molecule and the pterin ring = 77.1 (1)°]. N—HO, O—HN and O—HO hydrogen bonds link the complex molecules and lattice water molecules into a three-dimensional network. π–π interactions are observed between the pyrazine and pyrimidine rings [centroid–centroid distance = 3.437 (2) Å].