Copper(II) and Zinc(II) Complexes with Heterocyclic Acid Anions and 3,5-Dimethylpyrazole: Synthesis, Structure, and Biological Properties

The reaction of copper(II) and zinc(II) acetates with 3-furancarboxylic (HFur) and 2-thiophenecarboxylic (HTph) acids with subsequent addition of 3,5-dimethylpyrazole (HDmpz) gave mononuclear complexes [M(L)2(HDmpz)2] (M = Cu(II), L = Fur– (I), Tph– (II); Zn(II), L = Fur– (III)). The structures of compounds I–III were determined by X-ray diffraction. According to X-ray diffraction data, I and II are isostructural: the central Cu(II) atom occurs in a square planar environment formed by two oxygen atoms of carboxylate anions and HDmpz nitrogen atoms; in III, the Zn atom is in the tetrahedral environment of two furoate anions and HDmpz molecules, thus forming the {MO2N2} groups. The complexes are additionally stabilized in the crystal by inter- (I and II) and intramolecular (III) hydrogen bonds. The biological activity of I–III was determined in relation to the non-pathogenic Mycolicibacterium smegmatis.