Coumarin thiazole-derived Schiff base copper complex: synthesis, characterization, and applications in the catalytic degradation of dyes, pearl millet seed germination for improved agricultural output and antioxidant assays

Abstract

In this work, we report the synthesis, characterization, catalytic degradation of dyes, and antioxidant scavenging assay of a coumarin thiazole-derived Schiff base (CTSB) copper complex and its impact on pearl millet seed germination. The coumarin thiazole Schiff base ligand was synthesized from diethylamino salicylaldehyde and a coumarin thiazole-based amine. The catalytic degradation of organic dyes using the synthesized coumarin thiazole-derived Schiff base (CTSB) copper complex exhibited 99.89% degradation of methylene blue within 35.0 seconds, while 94.22% of rhodamine B was degraded at room temperature within 3.0 minutes upon exposure to sunlight under optimum reaction conditions. Moreover, 92.88% of Congo red and 70.65% of methyl orange were degraded within 20.0 minutes and 12.0 minutes, respectively, at room temperature upon exposure to sunlight; similar percentages of degradation were obtained within 12.0 minutes and 4.0 minutes, respectively, when they were exposed to ultraviolet light. Additionally, the coumarin thiazole-derived Schiff base (CTSB) copper complex exhibited outstanding antioxidant activity (90.59%) against DPPH assays. Further, the effect of the developed CTSB-copper complex on seed germination was examined on hybrid pearl millet seeds. Methylene blue and methyl orange exhibited approximately 30% and 17% reduction in seed germination, respectively, in comparison to the control. The treatment with the CTSB-copper complex neutralized the effect of methylene blue and methyl orange dyes on the percentage germination of hybrid pearl millet seeds. The present findings highlight the potential of the CTSB-copper complex as a sustainable material for environmental remediation and for various applications in agriculture and biological sciences.