Bipyridine adducts of Zn(II) and Ni(II) bis (N-methyl-N-phenyl dithiocarbamate): Synthesis, characterization, and biological applications

Abstract

Substituted bipyridine adducts of Zn(II) and Ni(II) bis (N-methyl-N-phenyl dithiocarbamate) have been synthesized by the reaction of the dithiocarbamate complexes with 4, 4′ bipyridine, 4, 4′-dimethyl- 2,2 bipyridine, 4,4′-dimethoxy-2,2′-bipyridine, 4,4′-ditertbutyl-2,2′ bipyridine. The resulting adduct were represented as [M(L)2(B)], [M(L)2(DMeB)], [M(L)2(DMxB)] and [M(L)2(DTB)] respectively, (where M= Zn/Ni), and characterized using elemental analysis, various spectroscopic techniques and X-ray single crystallography. The spectroscopic data suggest octahedral coordination around the metal center due to the formation of a new M-N bond with the nitrogen of the Lewis bases. A considerable shift occurred in the peaks found in the vicinity of the M-N coordination upon the formation of the adducts. Single crystal data obatined for [Zn(L)2(B)] and [Zn(L)2(DMeB)] revealed a five and six geometry respectively around the Zn center in the adducts. Furthermore, the compounds were evaluated for cytotoxicity, antioxidant, and anti-inflammatory properties. Although all the biological studies conducted generally revealed a concentration-dependent profile, no noticeable trends were found even with the compounds that exhibited structural similarities. Nevertheless, the compounds showed good activity, with IC50 ranging from 0.0003 to 17.38 µg/mL, which was better than the standard 5-Fluorouracil (5 FU) used in the cytotoxicity study. The adducts had a better antioxidant property in DPPH assay than in all the used antioxidant assays. Upon evaluation in a Bovine serum albumin denaturation assay, they also possessed a better anti-inflammatory property than diclofenac.