The Counterion (SO42− and NO3−) Effect on Crystallographic, Quantum-Chemical, Protein-, and DNA-Binding Properties of Two Novel Copper(II)–Pyridoxal-Aminoguanidine Complexes

• Published in: Crystals (Basel) Vol. 14; no. 9; p. 814
• Main Authors: Jevtovic, Violeta, Golubović, Luka, Alshammari, Odeh A. O., Alhar, Munirah Sulaiman, Alanazi, Tahani Y. A., Rakic, Violeta, Ganguly, Rakesh, Dimitrić Marković, Jasmina, Rakić, Aleksandra, Dimić, Dušan
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-09-2024
• Subjects: Atomic properties; Atomic structure; Binding; Cancer; Copper; copper(II) complexes; Crystal structure; Crystallography; CT-DNA; Cytotoxicity; DFT; Diabetes; Free radicals; Geometry; HSA; Hydrogen bonds; Ligands; Molecular docking; Nitrates; Nitrogen; Planar structures; Potassium iodides; Proteins; pyridoxal-aminoguanidine; Quantum chemistry; Quantum theory; Serum albumin; Spectrophotometry; Surface analysis (chemical); Titration
• ISSN: 2073-4352; 2073-4352
• DOI: 10.3390/cryst14090814

New Cu(II) complexes with pyridoxal-aminoguanidine (PLAG) ligands and different counterions (SO42− and NO3−) were prepared and their crystal structures were solved by the X-ray crystallography. The geometries of the obtained complexes significantly depended on the counterions, leading to the square-pyramidal structure of [Cu(PLAG)NO3H2O]NO3 (complex 1) and square-planar structure of [Cu(PLAG)H2O]SO4 (complex 2). The intermolecular interactions were examined using the Hirshfeld surface analysis. The theoretical structures of these complexes were obtained by optimization at the B3LYP/6-311++G(d,p)(H,C,N,O,S)/LanL2DZ(Cu) level of theory. The Quantum Theory of Atoms in Molecules (QTAIM) was applied to assess the strength and type of the intramolecular interactions and the overall stability of the structures. The interactions between the complexes and transport proteins (human serum albumin (HSA)) and calf thymus DNA (CT-DNA) were examined by spectrofluorometric/spectrophotometric titration and molecular docking. The binding mechanism to DNA was assessed by potassium iodide quenching experiments. The importance of counterions for binding was shown by comparing the experimental and theoretical results and the examination of binding at the molecular level.