Bis(2-aminomethyl-1H-benzimidazole-κ2 N 2,N 3)bis(nitrato-κO)copper(II)

In the title compound, [Cu(NO3)2(C8H9N3)2], the CuII atom, lying on an inversion center, has a distorted octahedral coordination environment defined by four N atoms from two chelating 2-aminomethyl-1H-benzimidazole ligands and two O atoms from two monodentate nitrate anions. In the crystal, N—H⋯O hydrogen bonds link the complex molecules into a three-dimensional network. An intramolecular N—H⋯O hydrogen bond is also observed.

In the title compound, [Cu(NO 3 ) 2 (C 8 H 9 N 3 ) 2 ], the Cu II atom, lying on an inversion center, has a distorted octahedral coordination environment defined by four N atoms from two chelating 2-aminomethyl-1H-benzimidazole ligands and two O atoms from two monodentate nitrate anions. In the crystal, N-HÁ Á ÁO hydrogen bonds link the complex molecules into a three-dimensional network. An intramolecular N-HÁ Á ÁO hydrogen bond is also observed.
Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL. ligand is a suitable model system for compounds of this sort, which is a bidentate ligand and can chelate a 3d metal ion through two nitrogen atoms of the pendant aminomethyl group and the imidazole ring (Gable et al., 1996;He et al., 2003;Jiang et al., 2004). Moreover, AMBI possesses a larger conjugated π-system and a nitrogen electron-donor of the secondary amine group, which has an important effect on the structures and functions of the complexes. On the other hand, metalloproteins that contain Cu are widespread. Characterization of model Cu complexes that mimic Cu proteins has led to a better understanding of the chemistry of Cu in biological systems. A new copper(II) complex with AMBI, which is reported in this paper, may be of interest with respect to both of the above-mentioned areas.
In the title compound, as shown in Fig. 1, two bidentate AMBI ligands are coordinated to the Cu II atom via two N atoms and two nitrate anions are coordinated to the Cu II atom via one O atom. The coordination geometry around the Cu II atom, which lies on an inversion center, is distorted octahedral, with a bite angle of 83.84 (5) Table 1, link the complex molecules into a three-dimensional network.

Experimental
The title compound was prepared by adding a methanol-water solution (4:1 v/v, 5 ml) of Cu(NO 3 ) 2 .3H 2 O (0.1 mmol) to a methanol solution (5 ml) of 2-(2-aminomethyl)benzimidazole (0.2 mmol) (Pascaly et al., 2001). The blue mixture was stirred at room temperature for 4 h and then filtered. Purple crystals suitable for X-ray diffraction were obtained by slow evaporation of the solvent after several days. Analysis, calculated for C 16

Bis(2-aminomethyl-1H-benzimidazole-κ 2 N 2 ,N 3 )bis(nitrato-κO)copper(II)
Crystal data 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 R-factors(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.