Structural investigation of group 10 metal complexes with thiosemicarbazone: crystal structure, mass spectrometry, Hirshfeld surface and in vitro antitumor activity

The current work reports the synthesis and structural investigation of three novel complexes with 2-acetyl-pyridine-N(4)-phenylthiosemicarbazone (HL1), [Ni(L-1)Cl] (1), [Pd(L-1)Cl] (2) and [Pt(L-1)PPh3]Cl center dot 2MeOH (3). The compounds were structurally characterized by means of single-crystal X-ray crystallography and spectroscopic techniques. All three complexes exhibit tetracoordinated metal centers in a square planar fashion with the thiosemicarbazone acting as a tridentateNNS-donor atoms. Intermolecular hydrogen bonds and pi center dot center dot center dot pi stacking interactions, building supramolecular assemblies in the complexes, were analyzed using the Hirshfeld surface. Mass spectrometry data showed the presence in solution of the characteristic fragmentation with the [M+H](+)molecular ion for all complexes. The thermochemical data, estimated by computational chemistry, allowed elucidate the relative intensity of the peaks present in the mass spectrum of the compounds investigated. The antitumor activity and selectivity of the free thiosemicarbazone ligand and their M(II) complexes (M = Ni, Pd, Pt) were evaluated against MCF-7, PBMC, and healthy cells. All compounds studied showed the death of cancer cells observing a great selectivity for the Ni(II) complex.