4-Aminoantipyrine Thiosemicarbazone Complexes with cobalt(II): Synthesis, Spectroscopic, Thermal, and Antibacterial Research

Abstract

An interesting series of cobalt(II) complexes of the new ligands: The antipyrinethiosemicarbazones 4[N-(benzalidene) amino]antipyrinethiosemicarbazone (BAAPTS), 4[N-(2-hydroxy-benzalidene)amino]antipyrinethiosemicarbazone (2b), and 4[N-(2-hydroxy-1-naphthalidene)amino]antipyrinethiosemicarbazone (2c) The complexes were discovered to have the typical stoichiometry [CoX2(H2O)(L)] and [Co(L)2](ClO4)2, where X = Cl, NO3, NCS, or CH3COO, and L =2a, 2b, or 2c. Elemental analyses, molar conductivity measurements, molecular weight estimations, magnetic moments at room temperature, infrared, and electronic spectra were used to describe the complexes. The behaviour of each and every thiosemicarbazone is that of neutral tridentate (N, N, S) donor ligands. The perchlorate complexes are 1:2 electrolytes, but the chloro, nitrato, thiocyanato, and acetate complexes are essentially non-electrolytes, according to the conductivity measurements in PhNO2 solution. Studies on thermodynamic behavior were conducted for a few typical complexes, and a decomposition process was suggested. The cobalt(II) complexes of the ligands and their antibacterial and antifungal activities have also been studied, and it has been found that the complexes are more effective bactericides than the ligands.