Diaqua(1,10-phenanthrolin-2-ol)nickel(II) dinitrate

In the mononuclear title complex, [Ni(C12H8N2O)2(H2O)2](NO3)2, the NiII ion is coordinated in a distorted octahedral geometry. The dihedral angle between the two mean planes defined by the phenanthroline ligands is 88.26 (6)°. Intra- and intermolecular O—H⋯O hydrogen bonds between the cation and the anions lead to the formation of a layered arrangement parallel to (010).

In the mononuclear title complex, [Ni(C 12 H 8 N 2 O) 2 (H 2 O) 2 ]-(NO 3 ) 2 , the Ni II ion is coordinated in a distorted octahedral geometry. The dihedral angle between the two mean planes defined by the phenanthroline ligands is 88.26 (6) . Intra-and intermolecular O-HÁ Á ÁO hydrogen bonds between the cation and the anions lead to the formation of a layered arrangement parallel to (010).

Comment
Metal complexes containing the derivatives of 1,10-phenanthroline as ligands play a pivotal role in the area of modern coordination chemistry. A few complexes dealing with 2-hydroxyl-1,10-phenanthroline have been published (Shi et al., 2009) and the interest in this area resulted in us to synthesize the title complex, and here we report its crystal structure, (I), Fig. 1.
The data of coordination bond lengths and associated angles indicate that the Ni II ion assumes a distorted octahedral geometry. All non-hydrogen atoms of the each ligand 2-hydroxyl-1,10-phenanthroline define a plane within 0.0300 Å (dealing with atom N1 plane) and 0.0200 Å (dealing with atom N3 plane) with the maximum deviation of 0.0506 (34)Å for atom N1 and of -0.0443 (33)Å for atom N4, respectively. The dihedral angle between the two planes is 88.26 (6)°, which means that two planes are almost vertical each other. In the crystal structure, there are the intramolecular O-H···O hydrogen bonds and the intermolecular O-H···O hydrogen bonds (Table 2), and the intermolecular O-H···O hydrogen bonds that are from nitrate anion and the coordinated H 2 O lead to the formation of a one-dimensional chain as shown in Fig. 2.
Experimental 5 ml of an aqueous solution of hydrated nickel nitrate (0.1745 g, 0.60 mmol) was added to 10 ml of a methanolic solution containing 2-hydroxyl-1,10-phenanthroline (0.1176 g, 0.60 mmol). Then NaOH (0.024 g, 0.60 mmol) was added into the mixed solution meanwhile it was stirred, and the mixture was further stirred for a few minutes. The green single crystals were obtained after the filtrate had been allowed to stand at room temperature for two weeks.

Refinement
H atoms of water molecules were located in a difference Fourier map and refined as riding, with O-H = 0.82-0.89 Å, U iso (H) = 1.5 U eq (O). Other H atoms were placed in calculated positions, and refined as riding with C-H = 0.93 /%A and U iso (H) = 1.2 eq (C).  Diaqua(1,10-phenanthrolin-2-ol)nickel(II) dinitrate Crystal data [Ni(C 12  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )