Dibromido(2,9-dimethyl-1,10-phenanthroline-κ2 N,N′)zinc

The reaction of equimolar amounts of zinc bromide and 2,9-dimethyl-1,10-phenanthroline in dry methanol provided the title compound, [ZnBr2(C14H12N2)], in good yield. The ZnII ion is coordinated in a distorted tetrahedral environment by two N atoms from the chelating 2,9-dimethyl-1,10-phenanthroline ligand and two bromide ions. There is intermolecular π–π stacking between adjacent phenanthroline units, with centroid–centroid distances of 3.594 (3) and 3.652 (3) Å.

The reaction of equimolar amounts of zinc bromide and 2,9dimethyl-1,10-phenanthroline in dry methanol provided the title compound, [ZnBr 2 (C 14 H 12 N 2 )], in good yield. The Zn II ion is coordinated in a distorted tetrahedral environment by two N atoms from the chelating 2,9-dimethyl-1,10-phenanthroline ligand and two bromide ions. There is intermolecular stacking between adjacent phenanthroline units, with centroid-centroid distances of 3.594 (3) and 3.652 (3) Å .
In the molecule of the title compound, (Fig. 1), the two N atoms of one phen ligand and two Br atoms are coordinated to Zn II atom in a distorted tetrahedral arrangement. The Zn-N bonds [average 2.062 Å] are somewhat shorter than the Zn -Br distances [average 2.328 Å] and they are closed to such bond lengths found in other discrete 1,10-phenanthroline derivatives of zinc complexes (Seebacher et al., (2004);Harvey et al.,(1999)). The two N atoms bite angle of phen ligand, N(2)-Zn(1)-N(1), significantly is smaller than N(2)-Zn(1)-Br(1)and N(1)-Zn(1)-Br(2). The bite angle in title complex is also similar to that of found in other zinc complexes of 1,10-phenanthroline, regardless of geometry of complex (Jordan et al.,(1991);Pallenberg et al.,(1997)).

Refinement
The C-H protons were positioned geometrically and refined as riding atoms with C-H = 0.93 Å and Uiso(H) = 1.2 Ueq(C) for aromatic C-H groups, C-H = 0.96 Å and Uiso(H) = 1.5 Ueq(C) for methyl groups.  The molecular structure of the title compound, ellipsoids drawn at 30% probability level.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq