Volume 49, Nº 10 (2023)

A final review of the results of studies of versatile biological activities (in vitro) of chiral metal complexes with benzylamine and ethylenediamine derivatives of terpenes is presented. The cytotoxic profiles of palladacycles containing a Pd–C bond and palladium and zinc chelate complexes were determined. For a number of compounds, the possible mechanisms of potential anticancer action were analyzed, such as modulation of mitochondrial functioning and effect on the parameters of glycolytic function of tumor cells. The antibacterial and antifungal activities of palladium complexes of different types and copper chelate complexes were investigated. A correlation between high antimicrobial activity and antioxidant properties was found for a number of copper complexes. The material is supplemented by an extended analysis of publications in relevant subjects.

The reaction of copper(II) acetate with 2-furancarboxylic (HFur)/5-nitro-2-furancarboxylic (HNfur) acids and 5-nitro-1,10-phenanthroline (Nphen) in methanol resulted in the formation of the binuclear coordination compounds [Cu2(L)4(Nphen)2]·X (L = Fur (I), Nfur (II); X = H2O (I)), which were structurally studied by direct X-ray diffraction (CCDC no. 2244205 (I) and 2244206 (II)). According to X-ray diffraction data, the coordination environment of the central metal ion in I and II is composed of two nitrogen atoms of Nphen and three oxygen atoms of the acid anions, which thus form the {CuN2O3} tetragonal pyramid in which the copper coordination number is five. Intermolecular hydrogen bonds and stacking interactions between the Nphen aromatic rings provide supramolecular stabilization of I and II. A characteristic feature of supramolecular organization of II is the presence of a coordination bond between the Cu2+ cation and oxygen of the Nphen NO2- group of parallel chains. A biological activity assay for complexes I and II concerning the cytotoxic properties against a human ovarian adenocarcinoma cell line (SKOV3) and the mycobacterial strain Mycolicibacterium smegmatis showed an efficient suppression of cell viability. The results of mathematical modeling of the probability of Cu2+ binding to amino acid residues of M. smegmatis proteins suggested the affinity of the Cu(II) ion to a number of amino acids in polypeptide sites. It was shown that metal ion binding in mycobacterial proteins is more characteristic of histidine- and glutamic acid-containing moieties.

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.