catena-Poly[[tetra­kis­(3,5-dimethyl-1H-pyrazole-κN2)copper(II)]-μ2-sulfato-κ2O:O′]: crystal structure and Hirshfeld surface analysis of a CuII coordination polymer.

The title coordination polymer, [Cu(SO₄)(C₅H₈N₂)₄]_n, was synthesized using a one-pot reaction of copper powder, anhydrous copper(II) sulfate and 3,5- dimethyl-1H-pyrazole (Hdmpz) in acetonitrile under ambient conditions. The asymmetric unit can be described as a chain consisting of four [Cu(SO₄)(Hdmpz)₄] formula units that are connected to each other by a 2- sulfato-bridged ligand. The octahedral coordination geometry (O₂N₄) 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 SO₄ tetrahedra. The CuCu distances within one asymmetric unit are in the range 7.0842 (12)–7.1554 (12) A˚ . 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 HH (74.7%), HO/OH (14.8%) and HC/ CH (8.2%) interactions. [ABSTRACT FROM AUTHOR]