Performance of new metal complexes for anionic and cationic dyes photodegradation: construction, spectroscopic studies, optical properties, and DFT calculations

Abstract

Water pollution is referred to as the introduction of exotic species into an ecosystem, which poses serious difficulties for both the environment and human health. As a result, water treatment has garnered a lot of interest in recent studies, particularly for dyes removal. In an effort to synthesize new photocatalysts with the highest potential for removing pollutants, photocatalytic degradation of two types of dyes; aniline blue, and malachite green by newly synthesized Ag(I), Ni(II), and Co(II) complexes photocatalysts has been investigated here. Ag(I), Ni(II), and Co(II) ions were used to interact with the novel imine ligand, HL, which was produced by condensing 3-acetylcoumarin, and sulfadimidine, in order to make the desired complexes. Different spectroscopic methods were used to properly characterize and confirm the structures of all synthesized compounds. The ligand, HL act as anionic tetradentate through the imine group (C=N), lactone carbonyl group (C=O), sulfonamide group (SO2NH), and pyrimidine ring nitrogen. The suggested formula of the synthesized complexes were [Ag2(L)(NO3)(H2O)3], [Co2(L)Cl3(H2O)].2H2O, and [Ni2(L)Cl3(H2O)].2H2O with a tetrahedral structure, and nonelectrolyte nature. Through optical studies and XRD measurements, all investigated compounds have the semiconductor nature and nano sizes. TGA-DTG/DSC techniques were utilized to thermal behavior study as well as assess some thermodynamic and kinetic parameters for all degradation stages. The geometry of the proposed structure of all new synthesized compounds was optimized by density functional theory (DFT) calculations. The BET surface area and the porosity data align well with the excellent photocatalytic performance for [Co2(L)Cl3(H2O)].2H2O complex toward the dyes degradation.