Synthesis and structural characterization of new gold(I) complexes as bioactive and antitumor agents

Abstract

New mononuclear gold(I) complexes based on 1-thiocarbamoyl-3,5-diaryl-pyrazoline ligands were synthesized and structurally characterized using X-ray crystallography, 13C and 1H NMR studies, and elemental analysis combined with FT-IR and UV-Vis spectroscopy. Complexes 1–3 were prepared in good yields and characterized by X-ray diffraction as neutral mononuclear complexes of the [Au(L)Cl] type with linear coordination geometry around AuI atoms. The UV-Vis absorption profiles of the compounds prepared exhibited two strong absorption bands between 225 and 400 nm, attributed to HOMO → LUMO electronic transitions of the (M + X)LCT type (charge transfer excitations arising from metal plus halogen to ligand) and mixed XLCT + IL type (charge transfer excitations arising from halogen to ligand plus intraligand), based on DFT studies. Assayed for antitumor activity against B16-F10 murine melanoma cells, 4 T1 murine mammary carcinoma cells, and a normal BHK-21 baby hamster kidney cells line, complexes 1–3 exhibited higher bioactivity and selectivity than their respective free ligands. The preliminary results showed these complexes to be good candidates for the development of new metallodrugs based on gold(I) compounds.