Two-Dimensional Supramolecular Organic Framework with Tunable Morphology and Luminescence Cascade-Enhanced Properties

Herein, a novel shape-controllable two-dimensional (2D) fluorescent supramolecular organic framework (CE-SOF) exhibiting assembly-induced emission enhancement was successfully synthesized by self-assembly of a coumarin-modified dibenzo-24-crown-8 derivative (G) with cucurbit[8]uril (CB[8]). It is possible to tune the topological morphology of free G from nanoparticles to nanosheets and octahedron-like 3D nanostructures, simply by the successive addition of CB[8] and dodecyl-modified sulfonatocalix[4]arene (SC4AD). Significantly, first-order and cascaded assembly resulted in 3.3 and 56.1 times increase in the fluorescence intensity of G, along with red shifts from 436 nm to 545 and 530 nm, respectively. When a pyridine cation-modified diarylethene derivative (DAE) as energy acceptor was introduced, photocontrolled energy transfer was realized, with the emission intensity of the CE-SOF being greatly quenched, enabling applications in multicolor anticounterfeiting. Moreover, the assemblies were applied for cell imaging and antibiotic detection.