Lan He

This review provides a discussion of developments in heteroatom-containing, carbon-bridged calixarene and thiacalixarene. These compounds are described with regard to their syntheses and inclusion properties.

Alkoxy side-chain-flanked diarylsulfonamide serves as a reliable structural motif for constructing macrocyclic aromatic tetrasulfonamides. This 90° structural motif is persistent both in solution and in the solid state, which allows the one-step formation of tetrasulfonamide macrocycles. These macrocycles adopt a cone-shaped conformation in solution and in the solid state. For each molecule, an interior cavity surrounded by the aromatic residues is formed. The cavity sizes of the macrocycles can be tuned by incorporating aromatic residues of proper sizes. Guest (solvent) molecules are found in the cavities and bound by side chains. In solution, ¹ H NMR shows that the cone conformations undergo rapid interconversion at room temperature. The alkoxy side chains are found to be indispensable for maintaining the cone conformation. In addition, these porous molecules self-assemble into hollow tubular structures in the solid state. A variety of host molecules and building blocks for constructing nanoporous solid-state structures can be expected from these molecules.

Aromatic tetrasulfonamide macrocycles carrying alkoxy side chains adopt a stable cone conformation in both the solid state and solution.

Synthesis and X-ray structural investigations have been carried out for the two title compounds, viz. C20H30N2O3S, (I), and C18H28N2O3S, (II). In both molecules, the cyclohexyloxy moiety and the conjugated cyclic system are located on opposite sides of the tetrahydrofuran-2-one ring. In the crystal structure of (II), there are two types of intermolecular hydrogen bonds, viz. C-H...S and N-H...O, and the molecules form a three-dimensional supramolecular architecture via the hydrogen bonds.