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

Abstract

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](CdI 4 )(C 2 H 3 N)} (1), {([syn/anti-did](HgI 4 )(C 2 H 3 N)} (2), {([syn/syn-did](Pb 2 I 8 )(PbI 5 )} (3), {([syn/syn-did](Bi 2 I 8 )(BiI 5 )} (4), {([syn/syn-did](Ag 4 Br 6 )} n (5), and {([syn/anti-did](Ag 2 I 4 )} (6) [did 2+ = (1 2 z, 5 2 z)-1 1 H, 5 1 H-1, 5(1, 3)-diimidazol-3-iuma-3, 7(1, 2)-dibenzenacyclooctaphane-1 3 , 5 3 -diium] have been synthesized through the self-assembly reaction of did 2+ 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 TiO 2 , so compounds 1-6 have semiconductor properties. Compound 1 has the smallest band gap value, and the photocatalytic performance is the best.