Asian Research Thesis Index

Abstract

In the present study, 52 different homoleptic and heteroleptic Pd(II) complexes were synthesized by reacting palladium(II) chloride with substituted triphenylphosphine and sodium salts of dithiocarbamates namely in a mixture of dry solvents. The ligands and various substituted triphenylphosphines used were sodium 4-benzylpiperazine-1-carbodithioate (L-1), sodium 4-diphenylmethylpiperazine-1-carbodithioate (L-2), sodium 4-(2-methoxyphenyl)piperazine-1-carbodithioate (L-3), sodium 4-(3-methoxyphenyl)piperazine-1-carbodithioate (L-4), sodium 4-benzylpiperidine-1-carbodithioate (L-5), sodium 4-(2-pyridyl)piperazine-1-carbodithioate (L-6), sodium 4-(2-pyrimidyl)piperazine-1-carbodithioate (L-7), sodium 4-(2-furoyl) piperazine-1-carbodithioate (L-8), sodium 4,4''-trimethylenedipiperidine-1-carbodithioate (L-9), tris(p-chlorophenyl)phosphine, tri-p-tolylphosphine, diphenyl-p-tolylphosphine, 1,4- bis(diphenylphosphino)butane, and tris(4-flourophenyl)phosphine. The coordination mode of ligands toward Pd(II), structural confirmation and geometry assignment of the complexes were made, using different analytical techniques such as elemental analysis, FT-IR, multinuclear (1H, 13C and 31P) NMR and X-ray single crystal analysis. Based on results, the ligand appeared to coordinate the Pd(II) atom through CSS moiety. The homoleptic and heteroleptic Pd(II) complexes demonstrate perfect square planner and distorted square planer geometries, respectively. The synthesized complexes were screened for in vitro cytotoxic activity against six different cell lines, LU (Lungs cancer cell lines), MCF-7 (mammary adenocarcinoma cell), 1c1c7 (murine hepatoma cells), PC-3 (prostate carcinoma), MDA-231 (estrogen-independent breast cancer cells) and HeLa (cervical carcinoma cell) by the MTT {Tetrazolium [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide} method. The homoleptic Pd(II) was less active whereas heteroleptic Pd(II) complexes composed of bidentate 1,4-bis(diphenylphoshino)butane, flouro and uncoordinated group (carbonyl and nitrogen) was found to be most active against different cancer cell lines as compare to the standard drug (Staurosporine and cisplatine). The interaction of the selected Pd(II) compounds with DNA was investigated by UV-Vis spectroscopy. The hypochromic effect for all the selected Pd(II) complexes was observed, indicating intercalative mode of interaction of these complexes with DNA. The antioxidant activity of selected Pd(II) complexes were evaluated using DPPH as a free radical and Ascorbic acid as a standard. Most of the complexes showed higher antioxidant property than the standard. The selected Pd(II) complexes were also evaluated to check their cytotoxicity and phytotoxicity using brine shrimp assay and seedling growth of maize, respectively. The highest activity was shown by compounds containing oxygenated species (19). Selected complexes were also screened for their antibacterial and antifungal activities against various strains of bacteria and fungi, and were found active.

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