The antiproliferative and antibacterial effects of copper(ii) complexes with the same ligand environment have been studied depending on the anion.

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.

The reaction of cymantrenates M[(OOС₅CH₄)Mn(CO)₃]₂(MeOH)₄ (M = Zn, Co(II), Ni(II)) with pyrazole (HPz) results in replacement of labile methanol molecules by the heterocyclic ligand and gives mononuclear complexes Zn[(OOCC₅H₄)Mn(CO)₃]₂(HPz)₂ (I), Ni[(OOCC₅H₄)Mn(CO)₃]₂(HPz)₄ (II), and Co[(OOCC₅H₄)Mn(CO)₃]₂(HPz)₄ (III). A similar reaction of cobalt cymantrenate with more basic and sterically bulky 3,5-dimethylpyrazole (HDmpz) gives the complex Co[(OOCC₅H₄)Mn(CO)₃]₂(HDmpz)₂ (IV). Compounds I–IV were characterized by X-ray diffraction (CCDC nos. 2157671 (I), 2157672 (II), 2157669 (III), and 2157670 (IV)), IR spectroscopy, and elemental analysis.

Four new frameworks were obtained by slow diffusion of a ligand solution – 1,2-bis(4-pyridyl)ethylene (dpe) into solutions of Ni^II and Co^II furoates. It is shown that, depending on the combination of solvents used, it is possible to purposefully set the topology of the coordination polymers as a simple chain in [Co(fur)₂(dpe)(CH₃OH)₂]_n (1), 2D 4-c sql in [Co(fur)₂(dpe)₂]_n (2)/[Ni(fur)₂(dpe)₂]_n (3) and 3D 3-cetb in [Ni(fur)₂(dpe)_1.5(H₂O)]_n·3H₂O (4) (fur⁻ is the anion of 2-furoic acid). The simple chains extend in two different directions. The sql nets show inclined polycatenation. Compound 4 exhibits the first example of such a high degree of interpenetration as 7, which is more than three times higher than the known record for nets. All the compounds were characterized by single crystal X-ray analysis. The metal atoms in the structural fragments have a CN = 6 and are in an octahedral environment with a different ratio of N and O – ({CoO₄N₂} (1), {MO₂N₄} for M = Co (2) and Ni (3), {NiO₃N₃} (4)). The coordination network of 4 has accessible channels with an estimated pore volume of 4650 ų per unit cell (29.4%). Thermal behavior of 1, 3 and 4 was studied by simultaneous thermal analysis (STA). The obtained χT(T) dependences were approximated using the PHI software. It was shown that interweaving results in the shortening of the metal–metal magnetic interactions.

Heteroleptic Zn₂Gd₂ and Zn₂Eu₂ complexes have been synthesized and their photophisical properties have been investigated. The complexes demonstrate antibacterial activity and cytotoxic effect on the cancer cells higher than on healthy fibroblasts.