Copper(II) Complexes with Substituted Thiosemicarbazones of α-Ketoglutaric Acid: Synthesis, X-ray Structures, DNA Binding Studies, and Nuclease and Biological Activity

New α-ketoglutaric acid thiosemicarbazone (H3ct) derivatives and their copper complexes were synthesized and
characterized by analytical and spectroscopic (IR and NMR) methods. For two of the ligands, Me-H3ct and Allyl-H3ct, and for a complex, [Cu(Me-Hct)(OH2)]n·2nH2O, the X-ray structures were also determined. In the latter the
copper atom shows a 4 + 1 pyramidal coordination, a water oxygen appears in the apical position, and three of
the basal positions are occupied by the SNO tridentate ligand and the fourth by a carboxylic oxygen of an adjacent
molecule that gives rise to a polymeric chain. DNA binding constants were determined, and studies of thermal
denaturation profiles and nuclease activity were also performed. Tests in vitro on human leukemia cell line U937
were carried out on cell growth inhibition, cell cycle, and apoptosis induction.