Anti-cancer activity of novel Schiff base copper (II) complex: synthesis and characterization

Abstract

A novel thiosemicarbazone substituted schiff base ligand and its Cu(II) complex have been prepared and characterized. Schiff bases are considered as an important pro ligand in coordination chemistry because they easily form stable complexes with biologically active transition metal ions. Such as Cu 2+, Zn2+, Ni2+ etc. In this paper, novel Cu (II) complexes of thiosemicarbazone ligands were synthesised by refluxing thiosemicarbazone substituted pro ligands with copper salts in 1:1 molar ratio in absolute ethanol under thermal condition at 80o c for 5-6 hour. The resulting brown coloured copper complexes were filtered and recrystallized from petroleum ether. In this synthesis, we use absolute ethanol as a polar environment for the synthesis of copper complexes from schiff base ligands because the use of polar solvent medium in synthesis plays a very important role in reducing minimum possibilities of side reactions which hinders the proper conversion of ligands into copper complexes and also reducing the reaction time. All synthesized compounds were characterized through various spectroscopic and pharmacological techniques. FT-IR, UVVis, NMR, Mass, TGA-DTA, XRD spectra techniques were used to confirm the structures of copper complexes and ligands. All compounds are thermal stable up to 350o c. The good results of pharmacological activities of compounds like in-vitro anti -oxidant and anti - cancer activity against DPPH and cisplatin drug, explained the presence of biologically active functional groups are present in ligands as well as their copper complexes. Results found that the copper complexes were more active than the ligands. The synthesis of copper complexes from thiosemicarbazone schiff base ligands in proper stoichiometic ratio is an excellent method of preparing pharmacological active compounds which can be considered as good anti -cancer drug candidate for the treatment of cancer.