Docking Studies, Cytotoxicity Evaluation and Interactions of Binuclear Copper(II) Complexes with S-Isoalkyl Derivatives of Thiosalicylic Acid with Some Relevant Biomolecules.

The numerous side effects of platinum based chemotherapy has led to the design of new therapeutics with platinum replaced by another transition metal. Here, we investigated the interactions of previously reported copper(II) complexes containing S-isoalkyl derivatives, the salicylic acid with guanosine-5'-monophosphate and calf thymus DNA (CT-DNA) and their antitumor effects, in a colon carcinoma model. All three copper(II) complexes exhibited an affinity for binding to CT-DNA, but there was no indication of intercalation or the displacement of ethidium bromide. Molecular docking studies revealed a significant affinity of the complexes for binding to the minor groove of B-form DNA, which coincided with DNA elongation, and a higher affinity for binding to Z-form DNA, supporting the hypothesis that the complex binding to CT-DNA induces a local transition from B-form to Z-form DNA. These complexes show a moderate, but selective cytotoxic effect toward colon cancer cells in vitro. Binuclear complex of copper(II) with S-isoamyl derivative of thiosalicylic acid showed the highest cytotoxic effect, arrested tumor cells in the G2/M phase of the cell cycle, and significantly reduced the expression of inflammatory molecules pro-IL-1ß, TNF-α, ICAM-1, and VCAM-1 in the tissue of primary heterotopic murine colon cancer, which was accompanied by a significantly reduced tumor growth and metastases in the lung and liver.

Synthesis, Crystal Structure, Theoretical Calculations, Antibacterial Activity, Electrochemical Behavior, and Molecular Docking of Ni(II) and Cu(II) Complexes with Pyridoxal-Semicarbazone.

New Ni (II) and Cu (II) complexes with pyridoxal-semicarbazone were synthesized and their structures were solved by X-ray crystallography. This analysis showed the bis-ligand octahedral structure of [Ni(PLSC-H)2]·H2O and the dimer octahedral structure of [Cu(PLSC)(SO4)(H2O)]2·2H2O. Hirshfeld surface analysis was employed to determine the most important intermolecular interactions in the crystallographic structures. The structures of both complexes were further examined using density functional theory and natural bond orbital analysis. The photocatalytic decomposition of methylene blue in the presence of both compounds was investigated. Both compounds were active toward E. coli and S. aureus, with a minimum inhibition concentration similar to that of chloramphenicol. The obtained complexes led to the formation of free radical species, as was demonstrated in an experiment with dichlorofluorescein-diacetate. It is postulated that this is the mechanistic pathway of the antibacterial and photocatalytic activities. Cyclic voltammograms of the compounds showed the peaks of the reduction of metal ions. A molecular docking study showed that the Ni(II) complex exhibited promising activity towards Janus kinase (JAK), as a potential therapy for inflammatory diseases, cancers, and immunologic disorders.

Theoretical modeling of sorption of metal ions on amino-functionalized macroporous copolymer in aqueous solution.

With regard to the harmful effects of heavy metals on human health and the environment, the demand for synthesis and investigation of macromolecules with large capacity of harmful substances sorption is ever greater. Quantum-chemical methods may be applied in structural modeling, prediction, and characterization of such molecules and reactions. Sorption of metal ions (Cu2+, Cd2+, Co2+, and Ni2+) to triethylenetetramine-functionalized copolymer poly(GMA-co-EGDMA)-teta was successfully modeled by quantum chemical calculations, at the B3LYP//6-311++G**/lanl2dz level. Optimized structures of metal complexes were used for calculation of real binding energy of metal ion within the complex (ΔEr). Solvent and hydrolyzation effects were essential for obtaining the objective values. Solvent effect was included in ΔEr by using the total solvation energy for reaction of formation of tetaOH complex (ΔEs1, the first approach) or by using dehydration energy of free metal ion (ΔEs2, the second approach). Experimental results were confirmed in our theoretical analyses (using the second approach). Graphical abstract Theoretical modeling of divalent metal ions sorption on triethylenetetramine-functionalized copolymer poly(GMA-co-EGDMA)-teta.

Orientations of axially coordinated imidazoles and pyridines in crystal structures of model systems of cytochromes.

Many properties of cytochromes and model systems depend on orientations of axial ligands. In this work, we elucidated the role of porphyrin substituents on orientation of axial ligands in model systems of cytochromes. The orientations of axially coordinated imidazoles and pyridines in crystal structures of model systems of cytochromes were analyzed and data were compared with previous quantum-chemical calculations. The results show that eight ethyl groups on porphyrin ring strongly favor parallel orientation, hence, in all these complexes axial ligands, pyridines or imidazoles, are mutually parallel. Four phenyl or mesityl groups at meso-carbons also favor parallel orientation but less strongly. Hence, in most of the bis-imidazole complexes the orientation is parallel, while in bis-pyridine complexes the orientation of pyridines depends on oxidation state of Fe. In bis-pyridine Fe(II) complexes orientation is parallel, in Fe(III) it is orthogonal. This analysis is in agreement with previous quantum-chemical calculations.