Volume 49, Nº 9 (2023)

Five coordination compounds [Cu2(Bipy)2L4]·C2H5OH (Iа, Ib), [Cu2(Dmbipy)2L4] (II),
[Cu2(Phen)2L4]·H2O (IIIa), [Cu2(Dmphen)2L4] (IVa), and [Cu2(Phendione’)2L4]·2C2H5OH·2H2O (V) are
synthesized from 5-(4-chlorophenyl)-1H-tetrazole (HL), where Bipy is 2,2'-bipyridine, Dmbipy is 4,4'-
dimethyl-2,2'-bipyridine, Phen is 1,10-phenanthroline, Dmphen is 4,7-dimethyl-1,10-phenanthroline, and
Phendione’ is 6-ethoxy-6-hydroxy-1,10-phenanthrolin-5-one. The crystal structures of the complexes are
determined by X-ray diffraction (XRD) of single crystals (CIF files CCDC nos. 2225368 (Ia), 2225369 (Ib),
2225370 (II), 2225372 (IIIa), 2225373 (IVa), and 2225371 (V)). The compounds are binuclear due to the
bridging function of the tetrazolate anion, and the coordination number of copper is five in all synthesized
complexes. The cytotoxic activity of the complexes against the Hep2 and HepG2 cancer cell lines and noncancerous
human fibroblasts MRC-5 is studied. The complexes exhibit pronounced cytotoxic properties, and
compound V has the maximum selectivity index with respect to the cancer cells.

A series of polymer complexes of Gd(III) and Eu(III) with 3-furancarboxylic (HFur) and 5-nitro-
2-furancarboxylic (HNfur) acids differed in the composition and coligands presented by solvent molecules
(CH3OH/C2H5OH/H2O) is synthesized: [Gd(Fur)3(CH3OH)(C2H5OH)]n (I), [Gd(Nfur)3(CH3OH)2]n·
CH3CN (II), [Eu(Fur)3(C2H5OH)]n (III), and [Eu(Nfur)3(H2O)2]n·3CH3CN (IV). According to the X-ray
diffraction (XRD) data, all complexes are 1D coordination polymers in which the lanthanide cation has the
coordination number 8 (LnO8) to form the environment as a doubly augmented triangular prism (I, II) or a
square antiprism (III, IV). The supramolecular levels of the polymers are stabilized due to intra- and intermolecular
hydrogen bonds between the coordinated solvent molecules and O atoms of the chelate-bound
anions of the acid and via two types of noncovalent C–H…O and N–O…π interactions that significantly contribute
to an additional stabilization of the crystal packings. The biological properties of complexes I, II, and
IV are studied with respect to the model nonpathogenic strain Mycolicibacterium smegmatis.

New gold(I) phosphine thiolate complexes [(Ph3P)Au(SLn)] I–V with Schiff bases LnSH containing
redox-active catechol, phenol, or quinone methide moieties were synthesized and characterized. The
molecular structure of compound I in the crystalline state was established by X-ray diffraction (CCDC
no. 2237815). The electrochemical behavior of compounds I–V was studieв by cyclic voltammetry. The proposed
electrooxidation mechanism of the complexes involves the Au–S bond cleavage, the disulfide formation,
as well as the oxidation of the redox active group of the ligand. In the cathode region, complexes I–III
tend to form relatively stable monoanionic species. The radical scavenging activity of complexes decreases in
comparison to free ligands in the reactions with synthetic radicals and the CUPRAC test. Compounds I, II,
IV, and V have no clear-cut effect on the promoted DNA damage; however, they show antioxidant action
in the non-enzymatic lipid peroxidation of rat liver homogenate. Compounds I–V demonstrate a weak antibacterial
activity against Staphylococcus aureus strains. The gold(I) complexes cytotoxicity was studied against
A-549, MCF-7, and HTC-116 cancer cell lines using MTT assay. The test compounds are characterized by
higher selectivity to certain types of cells than the sulfur-containing Schiff bases. The presence of quinone
methide moiety in the ligand in case of V significantly increases the cytotoxicity against all of the cell lines.

The polynuclear alanine hydroximate metallamacrocyclic complex Nd(C8H7NO4)(H2O)[15-
MCCu(II)Alaha-5](CH3COO) with the axial 3-hydroxy-4-pyridinone ligand is synthesized for the first time
from the (3-hydroxy-2-methyl-4-oxo-4H-pyridin-1-yl) acetate ligand. The X-ray diffraction (XRD) (CIF
file CCDC no. 2242224) and quantum chemical methods show that the interaction of ligand L with the Nd3+
ion retained due to ionic bonds with the oxygen atoms in the copper-containing metallamacrocyclic matrix
results in the formation of axial bonds (having a covalent contribution) between Nd3+ and the dioxolene fragment
of the pyridinone ligand. In topological and energy characteristics, these axial bond approach the bonds
of Cu2+ with the amine nitrogen atoms of the alanine hydroximate metallamacrocycle.