Monatshefte fur Chemie, cilt.156, sa.8-9, ss.857-865, 2025 (SCI-Expanded)
In this study, a leucine derivative ligand and its corresponding copper(II) complexes were synthesized and characterized using appropriate analytical techniques. Additionally, the molecular structures of ligand and one of the copper(II) complexes were determined by single-crystal X-ray diffraction method. X-ray diffraction studies revealed that there are two molecules in the asymmetric unit of ligand, which crystallizes in a monoclinic crystal system. A sheet structure parallel to the bc plane is formed by OH…O and CH…O type hydrogen bonds. [(R)-2-[[(1,3-Dimethyl-2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)methyl]amido]-4-methylpentanoate](1-methylimidazole) copper(II), which crystallizes in an orthorhombic crystal system, forms polymeric chains along the a-axis, while neighbouring chains form bi-chains through hydrogen bonding with solvent water molecules. The copper atom in [(R)-2-[[(1,3-dimethyl-2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)methyl]-amido]-4-methylpentanoate](1-methylimidazole) copper(II) adopts a square pyramidal geometry. Antioxidant activities of the compounds were examined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. (R)-2-[[(1,3-Dimethyl-2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)methyl]amino]-4-methylpentanoic acid, [(R)-2-[[(1,3-dimethyl-2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)methyl]amido]-4- methylpentanoate] triphenylphosphine copper(II), and bis[(R)-2-[[(1,3-dimethyl-2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)methyl]amido]-4-methylpentanoate](4-pyridyl) copper(II) exhibited higher antioxidant capacity than the other complexes in this study. The antibacterial and antifungal activities of the compounds were evaluated against a series of microbial species and compared with that of the free ligand. [(R)-2-[[(1,3-Dimethyl-2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)methyl]amido]-4-methylpentanoate](1-methylimidazole) copper(II) exhibited better biological activity than the ligand and other copper complexes against the tested microorganisms.