Unveiling the therapeutic potential of a Cu(II) complex with 1,10-phenanthroline and maleic acid: physicochemical characterization, DFT analysis, in silico pharmacokinetics, and evaluation of antitumor and antibacterial properties.

The crystal of a coordination compound of copper(II) with 1,10-phenanthroline (Phen) and maleic-acid (Mal) ligands, named as [Cu2(Phen)2(Mal)2]2H2O⋅CH3OH, was obtained by slow solvent evaporation method. The obtained complex was physicochemically and structurally characterized by powder X-ray diffraction (PXRD), thermogravimetry (TG) and differential thermal analysis (DTA), and by Fourier-transform infrared (FT-IR), Raman and ultraviolet-visible (UV-Vis) spectroscopies. Theoretical predictions using density functional theory (DFT) were performed to study the geometric, thermodynamic, electronic, and spectroscopic properties of the complex. PXRD results showed that the crystal has a monoclinic structure (C2/c-space group). The vibrational bands observed in the Raman and FT-IR spectra were assigned with support from DFT calculations results, which also revealed the influence of water, methanol, and their 1:1 mixture on the spectral profiles. Thermoanalytical measurements confirmed that the complex retains its coordination stability under biologically relevant conditions (∼310 K). UV-Vis spectroscopy revealed its maximum absorption at 646 nm, typical of bands related to the d-d transitions of Cu2+ ions. The characterization of the binuclear complex was complemented with the in silico studies of absorption, distribution, metabolism, and excretion (ADME), suggesting the potential of the complex as drug candidate. In vitro cytotoxicity analysis on MCF-7, MDA-MB-231, and HeLa cell lines foresees its potential use as anticancer, whereas bactericidal effects on gram-positive and gram-negative bacteria point out the promising antimicrobial properties of the complex.