S. Al-Jassabi

catena-Poly[[[tetra­kis­(4-methyl­pyridine-κN)copper(II)]-μ-sulfato-κ2 O:O′] 4.393-hydrate]

The structure of the title compound, {[Cu(SO4)(C6H7N)4]·4.393H2O}n, consists of Cu2+ ions surrounded in a square-planar fashion by 4-methylpyridine ligands, forming two crystallographically independent Cu{H3C(C5H4N)}4 units that are both located on crystallographic inversion centers. The Cu(4-methylpyridine)4 units are, in turn, connected with each other via bridging sulfate anions, leading to the formation of infinite [Cu{H3C(C5H4N)}4SO4]n zigzag chains along [001]. The completed coordination spheres of the Cu2+ ions are slightly distorted octahedral. The axial Cu—O bonds are elongated [average length = 2.42 (4) Å] compared to the equatorial Cu—N bonds [average length = 2.043 (2) Å]. The interstitial space between the chains is filled with uncoordinated water molecules that consolidate the structure through O—H⋯O hydrogen bonding. One of the five crystallographically independent solvent water molecules is partially occupied with an occupancy factor of 0.396 (4). Due to hydrogen bonding between symmetry-equivalent water molecules across inversion centers, several of the water H atoms are disordered in 1:1 ratios over mutually exclusive positions. The crystal under investigation was found to be non-merohedrally twinned in a 0.789 (1):0.211 (1) ratio by a 180° rotation around the reciprocal b axis.