Unusual saccharin-N,O (carbonyl) coordination in mixed-ligand copper(II) complexes: Synthesis, X-ray crystallography and biological activity

Abstract

Three tridentate Schiff bases containing N and S donor atoms were synthesised via the condensation reaction between S-2-methylbenzyldithiocarbazate with 2-acetyl-4-methylpyridine (S2APH); 4-methyl-3-thiosemicarbazide with 2-acetylpyridine (MT2APH) and 4-ethyl-3-thiosemicarbazide with 2-acetylpyridine (ET2APH). Three new, binuclear and mixed-ligand copper(II) complexes with the general formula, [Cu(sac)(L)] 2 (sac = saccharinate anion; L = anion of the Schiff base) were then synthesized, and subsequently characterized by IR and UV/Vis spectroscopy as well as by molar conductivity and magnetic susceptibility measurements. The Schiff bases were also spectroscopically characterised using NMR and MS to further confirm their structures. The spectroscopic data indicated that the Schiff bases behaved as a tridentate NNS donor ligands coordinating via the pyridylnitrogen, azomethine-nitrogen and thiolate-sulphur atoms. Magnetic data indicated a square pyramidal environment for the complexes and the conductivity values showed that the complexes were essentially non-electrolytes in DMSO. The X-ray crystallographic analysis

A Ternary Nickel(II) Schiff Base Complex Containing Di-Anionic and Neutral Forms of a Dithiocarbazate Schiff Base

“…They are potential sulfur-nitrogen donor ligands for metals and have been investigated since 1971 [1,2]. S-Alkyl dithiocarbazates are generally formed by the condensation reaction of aldehydes or ketones with dithiocarbazate derivatives [3]. The presence of the mixed hard-soft nitrogen-suylfur donor atoms makes them multifaceted ligands capable of coordinating a metal ion through these, as well as additional donor atoms, when present [4][5][6].…”