Studies on copper(II) complexes with β-alanine: Synthesis, X-ray crystal structure, cytotoxic activity, and DFT calculations

The present work is devoted to studies on the interaction of copper(II)- chloride, bromide, and nitrate with β-alanine (β-Ala, 3-aminopropanoic acid, NH 2 (CH 2 ) 2 COOH). The complex compounds [Cu 2 (μ 2 -β-Ala) 4 × 2 ]X 2 ∙nH 2 O X = Cl ( n = 1) (1) , Br ( n = 2) (2) , [Cu 2 (μ 2 -β-Ala) 4 (H 2 O) 2 ](NO 3 ) 4 ∙4H 2 O (3) have been prepared in aqueous solutions from the initial copper salts and β-Ala taken in the molar ratio of CuX 2 :β-Ala = 1:2. All the complexes have been characterized by the powder-, single crystal X-ray diffraction analysis, IR-, ESI-MS-spectroscopy, elemental analysis. The cytotoxic activity (MTT assay) on the postnatal human dental pulp stem cells (DPSC) and the MCF-7 breast cancer cell line was found to be the dose-dependent one for both types of cells, [Cu 2 (μ 2 -β-Ala) 4 Br 2 ]Br 2 ∙2H 2 O ( 2 ) demonstrating the highest difference in cytotoxicity for DPSC and MCF-7 at a concentration of 1∙10 −4 and 5∙10 −4 mol/L (survivability: 28.64 ± 2.08 and 5.44 ± 0.68 (MCF-7) and (61.57 ± 4.49 and 22.01 ± 1.74 % (DPSC)), in comparison with doxorubicin (Dox): 64.87 ± 12.68 % (DPSC); 68.97 ± 7.55 % (MCF-7)) at c = 1∙10 −4 mol/L. Quantum-chemical calculations (DFT method) allowed to predict the direction of complex formation and thermodynamic stability of the complexes obtained.