Synthesis, characterization and water treatment properties of bismuth iodide supramolecular compounds based on dicationic templates capped with n-aminopyridine group (n = 3, 4)

•Three new supramolecular materials with novel structures were prepared.•The three materials were tested and analyzed by FT-IR, EA, SCXRD, PXRD, TG-DTG.•The photocatalytic degradation performance and kinetics for tetracycline were studied.•The compounds 1 and 3 system has good catalytic degradation ability for tetracycline. In this study, three new organic cationic ligands, L1, L2, and L3 were synthesized using 1, 4-di(bromomethyl)benzene, 1, 3-dibromopropane, with n-aminopyridines (n = 3, 4) as starting materials. Supramolecular compounds 1–3 were then synthesized by reacting these ligands with inorganic metal salt bismuth iodide using both room-temperature volatilization and solvothermal methods. These compounds are [L1]2·[Bi2I10] (1), [L2]2·[Bi2I10] (2), and [L3]2·[Bi2I10] (3). Compounds 1–3 were characterized using X-ray single-crystal diffraction, X-ray powder diffraction, solid-state UV–Vis spectroscopy, and infrared spectroscopy. Additionally, we investigated the effects of factors such as the pH of the tetracycline (TC) solution and the amount of catalyst on the photocatalytic degradation of TC. We explored the optimal conditions for photocatalytic degradation of TC using compounds 1 and 3 and discussed the mechanism of photocatalytic degradation. [Display omitted] The design and synthesis of catalysts with high-intensity photocatalytic properties have been the focus of many researchers in recent years. On this basis, three new organic cationic ligands, L1, L2, and L3, were synthesized using 1,4-di(bromomethyl)benzene, 1,3-dibromopropane, with n-aminopyridines (n = 3,4) as starting materials. Supramolecular compounds 1–3 were then synthesized by reacting these ligands with inorganic metal salt bismuth iodide using both room-temperature volatilization and solvothermal methods. These compounds are [L1]2·[Bi2I10] (1), [L2]2·[Bi2I10] (2), and [L3]2·[Bi2I10] (3). Compounds 1–3 were characterized using X-ray single-crystal diffraction, X-ray powder diffraction, solid-state UV–Vis spectroscopy, and infrared spectroscopy. Additionally, we investigated the effects of factors such as the pH of the TC solution and the amount of catalyst on the photocatalytic degradation of TC. We explored the optimal conditions for photocatalytic degradation of TC using compounds 1 and 3 and discussed the mechanism of photocatalytic degradation.