Synthesis, characterization, and evaluation of silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine as biological agents

Five new silver(I) complexes were synthesized with mixed ligands of thiosemicarbazone derivatives and diphenyl(p-tolyl)phosphine in search of new biologically active compounds. A CHN elemental analysis, powder X-ray diffraction (PXRD) data and several spectroscopic techniques such as Fourier-transform infrared spectroscopy, energy-dispersive X-ray, 1 H, 13 C, and 31 P{ 1 H} NMR were performed to elucidate the structure of these complexes. Elemental analysis suggested that the stoichiometry of the complexes formed by the reaction of silver nitrate with thiosemicarbazone in the presence of (p-tolyl)PPh 2 was indeed 1:2:1 molar ratio. The silver ions were discovered to be coordinated to the sulfur of thiosemicarbazone and phosphorus of (p-tolyl)PPh 2 , having a tetrahedral geometry based on the spectroscopic data obtained. The PXRD patterns were studied to see the degree of crystallinity of the complexes. The in vitro antiproliferative activity of these complexes was investigated toward the MDA-MB-231 and MCF-7 breast cancer cell lines, as well as the HT-29 colon cancer cell line, which yielded IC 50 values in low micromolar range. The antiplasmodial activity of these complexes was also examined against chloroquine-resistant Plasmodium falciparum parasite which demonstrated good activity and further tested for their selectivity index. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group

New Silver Complexes with Mixed Thiazolidine and Phosphine Ligands as Highly Potent Antimalarial and Anticancer Agents

Five silver(I) complexes containing a mixed ligand system of phosphine and thiazolidine were successfully synthesized. The structural information of the complexes was assembled using various spectroscopic techniques such as CHN elemental analysis, Fourier transformed infrared (FTIR), 1 H, 13 C, and 31 P{ 1 H} NMR spectroscopy, and thermogravimetric analysis (TGA). A bidentate phosphine ligand acted as a chelating agent which bond to the silver in 1: 2 molar ratios. Meanwhile, thiazolidine was attached to the silver in a 1: 1 molar ratio. The antiplasmodial properties of all synthesized complexes were investigated on chloroquine-resistant P. falciparum parasite via HRP2 assays and cytotoxicity tests on Vero cells. Of all the synthesized complexes, complex 2 showed the highest SI value (more than 12.4) followed by complex 5 (6.6). The potent properties of compounds 2 and 5 were also noted in the in vitro antiproliferative assays involving MDA-MB-231 and MCF-7 breast cancer cell lines as well as HT-29 colon cancer cell line. Complex 2 was selective for MDA-MB-231 cells (GI 50 = 1.9 ± 0.3 μM), while complex 5 acted predominantly on breast carcinoma cells (GI 50 MDA-MB-231 = 4.7 ± 1.1 μM; MCF-7 = 2.9 ± 0.9 μM) instead of colon carcinoma (HT-29) cells (GI 50 = 15.1 ± 1.9 μM)