Conformational Dynamics of Monomer- versus Dimer-like Features in a Naphthalenediimide-Based Conjugated Cyclophane

The design and synthesis of an enantiomeric pair of 1,8-diethynylanthracene-bridged naphthalenediimide (NDI)-based cyclophanes ( Cyclo-NDI s) are reported. Each enantiomer of Cyclo-NDI exhibits a circularly polarized luminescence signal with a relatively large luminescence dissymmetry factor (g_lum=±8×10⁻³). We have further investigated the modulation of through-space electronic communication between co-facially oriented NDIs in a discrete Cyclo-NDI with changes in the temperature. Tuning of the electronic communication results from the conformational transformation of monomer- versus dimer-like features of Cyclo-NDI , as confirmed by UV/Vis, fluorescence, circular dichroic, and NMR spectroscopic analysis. The temperature-dependent optical response in the Cyclo-NDI through the conformational transformation could be utilized as a highly sensitive and reversible optical thermometer in a wide temperature range (100 to −80 °C).     

Flexible Zirconium MOFs as Bromine‐Nanocontainers for Bromination Reactions under Ambient Conditions

A series of flexible MOFs (PCN‐605, PCN‐606, and PCN‐700) are synthesized and applied to reversible bromine encapsulation and release. The chemical stability of these Zr‐MOFs ensures the framework's integrity during the bromine adsorption, while the framework's flexibility allows for structural adaptation upon bromine uptake to afford stronger host–guest interactions and therefore higher bromine adsorption capacities. The flexible MOFs act as bromine‐nanocontainers which elongate the storage time of volatile halides under ambient conditions. Furthermore, the bromine pre‐adsorbed flexible MOFs can be used as generic bromine sources for bromination reactions giving improved yields and selectivities under ambient conditions when compared with liquid bromine.     

Site‐Specific Pre‐Swelling‐Directed Morphing Structures of Patterned Hydrogels

Morphing materials have promising applications in various fields, yet how to program the self‐shaping process for specific configurations remains a challenge. Herein we show a versatile approach to control the buckling of individual domains and thus the outcome configurations of planar‐patterned hydrogels. By photolithography, high‐swelling disc gels were positioned in a non‐swelling gel sheet; the swelling mismatch resulted in out‐of‐plain buckling of the disc gels. To locally control the buckling direction, masks with holes were used to guide site‐specific swelling of the high‐swelling gel under the holes, which built a transient through‐thickness gradient and thus directed the buckling during the subsequent unmasked swelling process. Therefore, various configurations of an identical patterned hydrogel can be programmed by the pre‐swelling step with different masks to encode the buckling directions of separate domains.