Syntheses, Characterizations And Biological Properties Of Pyrrole Thiosemicarbazone Ligands And Their Complexes

Due to their extensive and outstanding biological activities such as antibacterial, antitumor, antiviral and anti-malaria, thiosemicarbazone compounds have received considerable attentions among the scientific researchers. Thus, thiosemicarbazone compounds play an increasing important role in medicine and pesticide fields. In this paper, syntheses and biological activities of thiosemicarbazone ligands and their metal complexes have been carried out, and the research prospects of such complexes have also been discussed.Herein, fifteen pyrrole thiosemicarbazone derivatives were synthesized by condension N4-substituted thiosemicarbazides with nitrogen containinig heterocyclic pyrrole aldehydes, and were also successfully characterized by 1H NMR, IR spectra, elemental analyses. Among them, the crystal structures of five ligands have been determined by X-ray diffraction. Meanwhile, series of transition metal Cu(II) or Ni(II) complexes have been synthesized and some of which were also confirmed by X-ray diffraction. Additionally, in order to evaluate their potential cancer chemotherapeutic abilities, MTT assays against human tumor cells PC-9, Eca109, SGC7901, A549 BGC823 or 8898 were carried out. The IC50 values indicated that the synthesized thiosemicarbazones compounds exhibited excellent inhibition in terms of the tumor cells used in the experiment, especially for the coordinated complexes, of which IC50 values remain under 40 μM. Therefore, it can be seen that pyrrole derivatived thiosemicarbazone complexes can be considered as potential antitumor drugs and may be applied to practice in the future.In conclusion, series of new thiosemicarbazone complexes were obtained by redecorating the molecular skeleton of thiosemicarbazones. New type of pesticides or medicines with high efficiency, low toxicity and low residue may be developed by using the features of significantly enhanced pharmacological activities of this kind of thiosemicarbazone compounds when coordinated with transition metal ions.