Bis(2,9-dimethyl-1,10-phenanthroline)copper(I) pentacyanidonitrosoferrate(II)

The asymmetric unit of the title complex [Cu(C14H12N2)2]2[Fe(CN)5(NO)], consists of a [Cu(dmp)2]+ cation (dmp is 2,9-dimethyl-1,10-phenanthroline) and half an [Fe(CN)5(NO)]2− anion. The anion is disordered across an inversion center with the FeII ion slightly offset (ca 0.205Å) from the inversion center in the direction of the disordered trans-coordinating CN/NO ligands. The anion has a distorted octahedral coordination geometry. The CuI ion is coordinated by two phenanthroline ligands in a distorted tetrahedral geometry. The dihedral angle between the phenanthroline ligands is 77.16 (4) Å. In the crystal, the cations are connected to the anions by weak C—H⋯N hydrogen bonds. In addition, weak π–π stacking interactions are observed, with centroid–centroid distances in the range 3.512 (3)–3.859 (3) Å.

The asymmetric unit of the title complex [Cu(C 14 H 12 N 2 ) 2 ] 2 -[Fe(CN) 5 (NO)], consists of a [Cu(dmp) 2 ] + cation (dmp is 2,9dimethyl-1,10-phenanthroline) and half an [Fe(CN) 5 (NO)] 2À anion. The anion is disordered across an inversion center with the Fe II ion slightly offset (ca 0.205Å ) from the inversion center in the direction of the disordered trans-coordinating CN/NO ligands. The anion has a distorted octahedral coordination geometry. The Cu I ion is coordinated by two phenanthroline ligands in a distorted tetrahedral geometry. The dihedral angle between the phenanthroline ligands is 77.16 (4) Å . In the crystal, the cations are connected to the anions by weak C-HÁ Á ÁN hydrogen bonds. In addition, weak stacking interactions are observed, with centroidcentroid distances in the range 3.512 (3)-3.859 (3) Å .

Experimental
Copper powder (0.04 g, 0.63 mmol), NH 4 Br (0.123 g, 1.25 mmol), Na 2 [Fe(CN) 5 (NO)] . 2H 2 O (0.188 g, 0.63 mmol) and dmp (0.262 g, 1.26 mmol) in DMF (30 ml) were heated to 333-343 K and stirred magnetically until total dissolution of copper was observed (2.5 h). Red needle-shaped crystals suitable for X-ray crystallography was isolated from the resulting dark-red solution with addition of 2-propanol and diethyl ether in a few days. The crystals (0.1 g, yield 30%) were filtered off, washed with dry methanol, and finally dried in vacuo at room temperature.

Refinement
All non-hydrogen atoms were refined isotropically. All hydrogen atoms were placed at calculated position and refined in a riding-model approximation. The symmetry realted Fe atoms are offset from an inversion centre by 0.214 Å and were refined with multiplicity 0.5. Atoms of disordered CN and NO groups occupy close positions and also were refined with multiplicity 0.5.

Figure 1
The molecular structure of the title compound with displacement ellipsoids drawn at the 30% probability level.

Figure 2
Part of the crystal structure with weak hydrogen bonds shown as dashed lines.

Bis(2,9-dimethyl-1,10-phenanthroline)copper(I) pentacyanidonitrosoferrate(II)
Crystal data [Cu(C 14   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.38 e Å −3 Δρ min = −0.31 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. 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.