(3-Acetyl-4-methyl-1H-pyrazol-1-ide-5- carboxylato)bis(1,10-phenanthroline)- nickel(II) 3.5-hydrate

R factor = 0.062; wR factor = 0.153; data-to-parameter ratio = 16.9. The title compound, [Ni(C7H6N2O3)(C12H8N2)2]3.5H2O, crystallizes as a neutral mononuclear complex with 3.5 solvent water molecules. One of the water molecules lies on an inversion centre, so that its H atoms are disordered over two sites. The coordination environment of NiII has a slightly distorted octahedral geometry, which is formed by one O and five N atoms belonging to the N,O-chelating pyrazol-1-ide-5-carboxylate and twoN,N0-chelating phenanthroline molecules. In the crystal, O—H O, N—H O and O—H N hydrogen bonds involving the solvent water molecules and pyrazole-5-carboxylate ligands form layers parallel to the ab plane. These layers are linked further via weak – interactions between two adjacent phenanthroline molecules, with centroid-to-centroid distances in the range 3.886 (2)–4.018 (1) Å, together with C—H contacts, forming a three-dimensional network. Related literature The work presented here continues studies of complexes based on pyrazolate ligands with transition metals, see: Klin-gele et al. (2009); Malinkin et al. (2009, 2012a,b,c); Ng et al. (2011); Penkova et al. (2008, 2009); Meyer & Pritzkow (2000); Bauer-Siebenlist et al. (2005); Świątek-Kozłowska et al. (2000)