Crystal structure of bis­[N-(2-hy­droxy­eth­yl)-N-methyl­dithio­carbamato-κ2 S,S′](pyridine)­zinc(II) pyridine monosolvate and its N-ethyl analogue

The common structural feature of the title compounds, [Zn(C4H8NOS2)2(C5H5N)]·C5H5N (I) and [Zn(C5H10NOS2)2(C5H5N)]·C5H5N (II), which differ by having di-thio-carbamate N-bound methyl (I) and ethyl (II) groups, is the coordination of each ZnII atom by two non-symmetrically chelating di-thio-carbamate ligands and by a pyridine ligand; in each case, the non-coordinating pyridine mol-ecule is connected to the Zn-containing mol-ecule via a (hy-droxy)O-H⋯N(pyridine) hydrogen bond. The resulting NS4 coordination geometry is closer to a square-pyramid than a trigonal bipyramid in the case of (I), but almost inter-mediate between the two extremes in (II). The mol-ecular packing features (hy-droxy)O-H⋯O(hy-droxy) hydrogen bonds, leading to supra-molecular chains with a zigzag arrangement along [10-1] (I) or a helical arrangement along [010] (II). In (I), π-π [inter-centroid distances = 3.4738 (10) and 3.4848 (10) Å] between coordinating and non-coordinating pyridine mol-ecules lead to stacks comprising alternating rings along the a axis. In (II), weaker π-π contacts occur between centrosymmetrically related pairs of coordinating pyridine mol-ecules [inter-centroid separation = 3.9815 (14) Å]. Further inter-actions, including C-H⋯π(chelate) inter-actions in (I), lead to a three-dimensional architecture in each case.