Intramolecular Cation‐π Interactions Organize Bowl‐Shaped, Luminescent Molecular Containers

Abstract

AbstractMolecules with nonplanar architectures are highly desirable due to their unique topological structures and functions. We report here the synthesis of two molecular containers (1 ⋅ 3Br− and 1 ⋅ 3Cl−), which utilize intramolecular cation‐π interactions to enforce macrocylic arrangements and exhibit high binding affinity and luminescent properties. Remarkably, the geometry of the cation‐π interaction can be flexibly tailored to achieve a precise ring arrangement, irrespective of the angle of the noncovalent bonds. Additionally, the C−H⋅⋅⋅Br− hydrogen bonds within the container are also conducive to stabilizing the bowl‐shaped conformation. These bowl‐shaped conformations were confirmed both in solution through NMR spectroscopy and in the solid state by X‐ray studies. 1 ⋅ 3Br− shows high binding affinity and selectivity: F−>Cl−, through C−H⋅⋅⋅X− (X=F, Cl) hydrogen bonds. Additionally, these containers exhibited blue fluorescence in solution and yellow room‐temperature phosphorescence (RTP) in the solid state. Our findings illustrate the utility of cation‐π interactions in designing functional molecules.