Light triggered encapsulation and release of C60 with a photoswitchable TPE-based supramolecular tweezers

Abstract

Stimuli responsive hosts for C 60 can control its binding and release on demand. A photoswitchable TPE based supramolecular host can encapsulate C 60 in the Z -form with a markedly different visual change in the colour. In addition, the Z -1 bound C 60 has been characterized by various spectroscopic methods and mass spectrometry. Upon exposure to visible light (>490 nm), the host switches to the E -form where the structural complementarity with the guest is destroyed as a result of which the C 60 is disassembled from the host. The results described herein reveals an actionable roadmap to pursue further advances in component self-assembly particularly light-induced association and dissociation of a guest molecule.

Photoswitchable Molecular Glue for Carbon Nanotubes Reversibly Controls Electronic Mobility with Light

“…Recently, we have studied the selective capture of C 60 using smaller TPE derivatives. 50 Thus, we studied the interaction of both trans-and cis-isomers of TPE-1 with carboxylic acid functionalized MWCNTs. For trans-TPE-1 in THF, increasing the amount of MWCNT in the solution (MWCNT was dispersed in the THF solution) led to a decrease in peak intensity at 405 nm in the UV−vis spectrum, along with an 8 nm red-shift and the formation of a new band at 580 nm (Figures 3A and S12A).…”

“…The tetraphenylethylene (TPE) unit with four phenyl groups, a well-studied system for its aggregation-induced emission (AIE) properties, serves as an excellent candidate as a building block for the receptors of carbon-based frameworks. 49,50 Among common photochromic molecules (diarylethenes, 51 spiropyrans, 52 oxazines, 53 stilbenes, 54 and azobenzenes), azobenzenes respond to two main external stimuli, light and heat, to reversibly switch between the isomers with different properties. Azobenzene switches from the thermodynamically favored trans-isomer to the cis-isomer upon exposure to ultraviolet (UV) light.…”

“…Controlled reversible photoswitching of conductivity is of particular interest in molecular electronics and has been a subject of interest by several groups recently. , However, it remains a challenging task to control the conductivity reversibly using an external stimulus at the molecular level. The tetraphenylethylene (TPE) unit with four phenyl groups, a well-studied system for its aggregation-induced emission (AIE) properties, serves as an excellent candidate as a building block for the receptors of carbon-based frameworks. , …”

Metal Ion Mediated Instant Z → E Isomerization of Azobenzene Macrocycles in the Absence of Light

“…Molecular switches such as diarylethene, spyropyran, , and azobenzene − have gained considerable attention owing to their potential use in molecular devices to switch the mechanical and optical properties of a wide range of materials as well as provide a means for controlling the catalytic activity by light. − Azobenzenes are extensively used due to their robustness, easy functionalization, and large changes in the geometry and the associated molecular properties upon exposure to light . Cyclic azobenzenes often display enhanced switching compared to their acyclic analogs. , They are thermally stable in the E -form and convert into the Z -form upon exposure to UV light.…”

Diversiform Nanostructures Constructed from Tetraphenylethene and Pyrene-Based Acid/Base Controllable Molecular Switching Amphiphilic [2]Rotaxanes with Tunable Aggregation-Induced Static Excimers

“…For example, tetraphenylethene (TPE) and its derivatives are weakly emissive or nonemissive in dilute solutions, but they emit efficiently in the aggregated or solid states, which may arise due to restricted intramolecular rotation (RIR). Fascinated by this intriguing phenomenon, a large number of AIEgens, with diversified architectures and versatile properties, have been generated and applied in organic light-emitting devices, biological imaging, organelles imaging, and drug delivery monitoring. − In 2019, Yang and co-workers reported that in the presence of Hg 2+ , the RIR will be effected by host–guest interaction between the TPE bridge and the pillar[6]­arene functionalized arms . However, to the best of our knowledge, to date, only few examples of MIM-based AIE active reversible molecular switching have been reported to be operational in aqueous media. − In our previous work, we described that TPE–calix[4]­arene-functionalized MIM-based reversible molecular switching supramolecular amphiphiles manifested their fluorescence emission, distinct nanostructures, and gelation properties could be induced by the multinoncovalent interactions during the self-assembly processes .…”