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.