Thiophene bearing Bis-Chalcone based monomers and polymers for environmental applications

Abstract

In this study, we have synthesized and characterized two bis-chalcones, MTCA and MTCM, both containing thiophene units. MTCA proved to be an excellent colorimetric probe for the rapid and selective detection of bisulfite/sulfite anions in aqueous solutions and real samples. This probe operates through a Michael addition reaction, facilitated by the cationic micellar media CTAB. The1,4- Michael addition serves as an effective method for determining SO 2 toxicity, expressed in terms of the collective concentration of bisulfite and sulfite anions. The probe showed high selectivity and sensitivity toward bisulfite and sulfite over other comparable anions, with a detection limit of 0.43 μM and 0.23 μM respectively.Owing to the presence of terminal thiophene units, we attempted to use these monomers to develop a new class of polymers with a donor-л-acceptor-л-donor type of repeating units. To the best of our knowledge, we are the first to report this kind of synthesized polymers; PTCA and PTCM. By employing FeCl 3 mediated oxidative coupling reaction, we could achieve the template-free synthesis of mesoporous polymers which is not commonly known. The novelty of our work lies here. Moreover, FeCl 3 -promoted oxidative coupling polymerization offers an added advantage of facile, low-cost, and large-scale syntheses.The porous structure, presence of heteroatoms, and electron-rich thiophene rings make these polymers ideal for environmental applications, including iodine capture, heavy metal ion removal, and organic dye adsorption. PTCA and PTCM exhibited impressive maximum iodine capture capacities of 242 wt.% and 221 wt.%, respectively. The maximum adsorption capacity of the polymer PTCA for Zn 2+ and Pb 2+ ions were obtained as 729.4 mg/g and 569.1 mg/g respectively, and the maximum adsorption capacity of the polymer PTCM for Zn 2+ and Pb 2+ was calculated as 652.7 mg/g and 545.1 mg/g respectively. Notably, both polymers displayed significant adsorption capacities for crystal violet, with PTCA reaching an adsorption capacity of 151.49 mg/g and PTCM reaching an adsorption capacity of 142.28 mg/g. Importantly, these polymers exhibited recyclability and reusability over five cycles without a significant loss of efficiency toward various adsorbates.