Dichlorido(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline-κ2 N,N′)mercury(II) acetonitrile hemisolvate

The asymmetric unit of the title compound, [HgCl2(C26H20N2)]·0.5CH3CN, contains two crystallographically independent [HgCl2(C26H20N2)] molecules and one acetonitrile solvent molecule. The HgII atoms are four-coordinated in distorted tetrahedral configurations by two N atoms from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline ligands and two Cl atoms. The ligand ring systems are not planar. The phenyl rings are oriented at dihedral angles of 74.61 (3) and 66.00 (3)° in the two molecules. In the crystal structure, π–π contacts between phenanthroline rings [centroid–centroid distances = 3.809 (1), 3.686 (1), 3.986 (1), 3.877 (1), 3.697 (1), 3.789 (1), 3.745 (1), 3.797 (1) and 3.638 (1) Å] may stabilize the structure.


Related literature
For Hg II X 2 complexes (X=Br, Cl, I and SCN)
We are grateful to Damghan University of Basic Sciences and Islamic Azad University, Shahr-e-Rey Branch, for financial support.

S2. Experimental
For the preparation of the title compound, (I), a solution of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (0.36 g, 1.10 mmol) in HCCl 3 (20 ml) was added to a solution of HgCl 2 (0.30 g, 1.10 mmol) in acetonitrile (20 ml) and the resulting pale yellow solution was stirred for 20 min at room temperature. Then, it was left to evaporate slowly at room temperature. After one week, colorless needle crystals of the title compound were isolated (yield; 0.47 g, 72.0%).

S3. Refinement
H atoms were positioned geometrically, with C-H = 0.93 and 0.96 Å for aromatic and methyl H, respectively, and constrained to ride on their parent atoms, with U iso (H) = 1.2U eq (C).

Figure 1
The molecular structure of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 40% 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.