A photoswitchable [2]catenane receptor.

A [2]catenane-based receptor functionalized with stiff-stilbene can be reversibly switched with 340/385 nm light between its - and -isomers, which leads to a considerable change in chloride binding affinity. Photoisomerization in the presence of chloride allows for on demand guest uptake and release.

Photoswitching of halide-binding affinity and selectivity in dithienylethene-strapped calix[4]pyrrole.

Dithienylethene-strapped calix[4]pyrrole is isomerized by 300/630 nm light between ring-open and -closed isomers, which affects the size of the anion binding site. Where for chloride this results in only a small change in affinity, that of the larger bromide and iodide ions is majorly affected, resulting in altered selectivity.

Photoswitchable molecular tweezers: isomerization to control substrate binding, and what about ?

The linkage of two identical binding motifs by a molecular photoswitch has proven to be a straightforward and versatile strategy to control substrate binding affinity by light. Stimulus control of binding properties in artificial receptors is partly inspired by the dynamic behavior of proteins and is highly attractive as it could, for example, improve extraction processes and allow (de)activation of membrane transport on demand. This feature article summarizes the development and design principles of molecular tweezers containing a molecular photoswitch as the core unit.

A photoswitchable strapped calix[4]pyrrole receptor: highly effective chloride binding and release.

A stiff-stilbene strapped calix[4]pyrrole receptor can be reversibly switched by light between a strong chloride-binding -isomer and a very weakly binding -isomer. The light-induced switching process is monitored by UV-Vis and H NMR spectroscopy and chloride binding is studied in detail using both H NMR and ITC titrations in DMSO and MeCN. In DMSO, at millimolar concentrations, switching from a fully bound to an almost fully unbound state can be triggered.

Modulation of porosity in a solid material enabled by bulk photoisomerization of an overcrowded alkene.

The incorporation of photoswitchable molecules into solid-state materials holds promise for the fabrication of responsive materials, the properties of which can be controlled on-demand. However, the possible applications of these materials are limited due to the restrictions imposed by the solid-state environment on the incorporated photoswitches, which render the photoisomerization inefficient. Here we present responsive porous switchable framework materials based on a bistable chiroptical overcrowded alkene incorporated in the backbone of a rigid aromatic framework.