catena -Poly[[tetra-kis-(3,5-dimethyl-1 H -pyrazole-κ N 2 )copper(II)]-μ 2 -sulfato-κ 2 O : O ']: crystal structure and Hirshfeld surface analysis of a Cu II coordination polymer.

The title coordination polymer, [Cu(SO 4 )(C 5 H 8 N 2 ) 4 ] n , was synthesized using a one-pot reaction of copper powder, anhydrous copper(II) sulfate and 3,5-dimethyl-1 H -pyrazole (Hdmpz) in aceto-nitrile under ambient conditions. The asymmetric unit can be described as a chain consisting of four [Cu(SO 4 )(Hdmpz) 4 ] formula units that are connected to each other by a μ 2 -sulfato-bridged ligand. The octa-hedral coordination geometry (O 2 N 4 ) of all copper atoms is realized by coordination of four pyrazole ligands and two sulfate ligands. Four pyridine-like N atoms of the pyrazole ligands occupy the equatorial positions, while two oxygen atoms of two sulfate ligands are in axial positions. As a result of the sulfate ligand rotation, there is a pairwise alternation of terminal O atoms (which are not involved in coordination to the copper atom) of the SO 4 tetra-hedra. The Cu⋯Cu distances within one asymmetric unit are in the range 7.0842 (12)-7.1554 (12) Å. The crystal structure is built up from polymeric chains packed in a parallel manner along the b -axis direction. Hirshfeld surface analysis suggests that the most important contributions to the surface contacts are from H⋯H (74.7%), H⋯O/O⋯H (14.8%) and H⋯C/C⋯H (8.2%) inter-actions.