Synthesis of dimeric thio-schiff base derivatives with nano-cerium(IV) oxide catalysts, characterization of structures, investigation of their thermal stability and biological activities

In this work, first, CeO2 nanoparticles, which can be used as catalysts in many reactions, were synthesized by preparing aqueous solution of cerium(III) nitrate hexahydrate in basic medium. In the second step, dimeric disulfide Schiff bases were synthesized via reaction of 2,2'-diaminodiphenyl disulfide with various aromatic aldehydes with nano-sized cerium(IV) oxide catalyst and without catalyst. Effect of catalyst on some parameters such as reaction time and yield of product were investigated. The morphology and crystal features of synthesized CeO2 nanocatalyst were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), but also nanocatalyst and compounds structures were illustrated by raman spectroscopy, fourier transform infrared (FT-IR) spectroscopy, UV-vis spectroscopy and fluorescence spectroscopy and their thermal stability was determined by thermogravimetric analysis (TGA) / differential thermal analysis (DTA). The antimicrobial and antifungal activity levels of the synthesized compounds on some Gram positive and Gram negative bacteria and yeast were determined by Disk Diffusion method and antimicrobial activity levels were compared with comparable antibiotics.