Synthesis, crystal structure and biological evaluation of Ni(II) complexes containing 4-chromone-N(4)-substituted thiosemicarbazone ligands

New nickel(II) complexes containing 4-chromone N(4)-substituted thiosemicarbazone ligands of the type [Ni(L1-3)(2)](NO3)(2)center dot H2O (1-3) [4-chromone-4-methylthiosemicarbazone (L-1), 4-chromone-4-phenylthiosemicarbazone (L-2), 4-chromone-4-cyclohexylthiosemicarbazone (L-3)] were synthesized and characterized by analytical and various spectroscopic techniques. The single crystal X-ray diffraction study of the complex 1 revealed a distorted octahedral geometry around the metal center. The new complexes were subjected to biological investigations such as DNA/protein interaction studies and in vitro cytotoxic study against human breast cancer cell line (MCF-7). The DNA binding by fluorescence spectral study showed that the complexes bind to DNA via intercalation binding mode. Protein binding studies using fluorescence spectroscopy showed that the new complexes could bind strongly with bovine serum albumin (BSA). The complexes have good anticancer activity against MCF-7 cancer cell line due to the terminal substituted thiosemicarbazones. (C) 2016 Elsevier Ltd. All rights reserved.