Synthesis, characterization, antioxidant, antileishmanial, anticancer, DNA and theoretical SARS-CoV-2 interaction studies of copper(II) carboxylate complexes.

Copper(II) carboxylate complexes [Cu(OOCR)L] () and [Cu(OOCR)OCO(R)CuL] (), where  = 2-methyl pyridine,  = 2-chlorophenyl acetate and R` = 2-fluorophenyl acetate were synthesized and characterized by FT-IR spectroscopy and single crystal X-ray analysis. Complex exhibits the typical paddlewheel array of a dinuclear copper(II) complex with carboxylate ligands. In complex , this scaffold is further extended into a polymeric arrangement based on alternate paddlewheel and square planar moieties with distinct coordination spheres. The complexes showed better 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activities and have been found to be more potent antileishmanial agents than their corresponding free ligand acid species. UV-Vis absorption titrations revealed good DNA binding abilities {Kb = 9.8 × 10 M () and 9.9 × 10 M ()} implying partial intercalation of the complexes into DNA base pairs along with groove binding. The complexes displayed cytotoxic activity against malignant glioma U-87 (MG U87) cell lines. Computational docking studies further support complex-DNA binding by intercalation. Molecular docking investigations revealed probable interactions of the complexes with spike protein, the nucleocapsid protein of SARS-CoV-2 and with the angiotensin converting enzyme of human cells.