Crystal structure of dichloridobis(1,3-diisopropyl-4,5-dimethyl-2H-imidazole-2-thione-κS)zinc(II)

The molecular structure of the title compound, [ZnCl2(C11H20N2S)2], shows tetrahedral Zn coordination from two Cl ligands and two thione groups. The Zn—Cl bond lengths differ sligthly at 2.2310 (10) and 2.2396 (11) Å while the Zn—S bond lengths are equal at 2.3663 (9) and 2.3701 (10) Å. The Cl—Zn—Cl angle is 116.04 (4) and S—Zn—S is 101.98 (3)°. All other angles at the central Zn atom range from 108.108 (3) to 110.21 (4)°. The C—S—Zn angles are 100.75 (10) and 103.68 (11)°, the difference most probably resulting from packing effects, as both the C—S and both the S—Zn bonds are equal in each case. The two imidazole ring planes make a dihedral angle of 67.9 (1)°. The CH3 groups of one isopropyl moiety are disordered over two sets of sites with occupation factors of 0.567 (15) and 0.433 (15). It may be noteworthy that the isomolecular Cu complex shows a different crystal packing (group–subgroup relation) with the Cu atom lying on a twofold rotation axis. In the crystal, the shortest non-bonding contact is a C—H⋯Cl interaction. This leads to the formation of centrosymmetric dimers that are stacked along the c-axis.

Supporting information for this paper is available from the IUCr electronic archives (Reference: HP2069).

S2. Refinement
Hydrogen atoms were clearly identified in difference syntheses, refined at idealized positions riding on the carbon atoms with C-H 0.98-1.00 Å and with isotropic displacement parameters U iso (H) = 1.2U eq (C) or 1.5U eq (-CH 3 ). All CH 3 hydrogen atoms were allowed to rotate but not to tip. The disordered positions (C141/142 and C151/152) of isopropyl moiety at C13 were refined with site occupation factors 0.57 (1) and 0.43 (1), respectively and DFIX 1.50 0.01 restraints.
Anistropic refinement of these disordered parts resulted in poor convergence, so eventually isotropic refinement was used.

Figure 1
Molecular structure of the title compound with anisotropic displacement parameters drawn at the 50% probability level.
Both orientations of disordered isopropyl group at C13 shown.  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.70 e Å −3 Δρ min = −0.79 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.