Hybrid Supramolecules for Azolium-Linked Cyclophane Immobilization and Conformation Study: Synthesis, Characterization, and Photocatalytic Degradation

In this paper, one imidazole macrocyclic divalent cation with a flexible configuration was chosen with the aim of the immobilization of its conformation. Six novel organic-inorganic hybrid supramolecules {([syn/anti-did](CdI4)(C2H3N)} (1), {([syn/anti-did](HgI4)(C2H3N)} (2), {([syn/syn-did](Pb2I8)(PbI5)} (3), {([syn/syn-did](Bi2I8)(BiI5)} (4), {([syn/syn-did](Ag4Br6)} n (5), and {([syn/anti-did](Ag2I4)} (6) [did2+ = (12z, 52z)-11H, 51H-1, 5(1, 3)-diimidazol-3-iuma-3, 7(1, 2)-dibenzenacyclooctaphane-13, 53-diium] have been synthesized through the self-assembly reaction of did2+ with different metals under solvothermal reaction. These compounds have been unambiguously confirmed by powder X-ray diffraction, IR, thermogravimetric and X-ray single-crystal diffraction. Crystallographic analysis shows that the anions of compounds 1 and 2 are isostructural with mononuclear anion structure, the anions of compounds 3, 4, and 6 are of binuclear structure, and compound 5 anion is a one-dimensional anionic chain structure. Imidazole cyclophanes of organic cations may exist in a syn/syn-conformation in 3-5 or syn/anti conformation in 1, 2, 6, but tilting angles in compounds 1-6 were different. This article described the photocatalytic degradation of organic dye in waste water and the optical band gap of compounds 1-6. The calculated semiconductor band gap of compounds 1-6 is smaller than that of TiO2, so compounds 1-6 have semiconductor properties. Compound 1 has the smallest band gap value, and the photocatalytic performance is the best.