Programmable photoresponsive materials based on a single molecule via distinct topochemical reactions

Abstract

Two crystals with different hierarchical architectures are observed based on a single molecule, achieving different types of [2 + 2] photocycloaddition. Finally, controllable photoactuators and light-writable materials are successfully fabricated.

Morphology-dependent photoresponsive behaviors of a self-assembled system based on a single cyanostilbene derivative

“…Such spectral changes indicated the shortening of the effective length of the conjugated psystem under irradiation, which was commonly thought to be a [2+2] cycloaddition process. 40,41 To prove this speculation, further experiments were carried out, which were in good agreement with other cycloadduct systems. As for the FT-IR spectra, the cyano stretching band changed from 2201 cm À1 to 2229 cm À1 upon irradiation (Fig.…”

“…4c). 41,42 MALDI-TOF mass spectroscopy studies provided more details about the photochemical product. A series of VOE oligomers were found on the mass spectrum, including dimers {m/z: around 1747.6 [m/z: around 2VOE + Na + ]}, trimers {m/z: around 2609.1 [3VOE + Na + ]} and tetramers {m/z: around 3473.9 [4VOE + Na + ]} (Fig.…”

Rapidly responsive liquid metal/polyimide photothermal actuators designed based on the bilayer structure difference in coefficient of thermal expansion

“…The bending angle increased approximately linearly with the increase of power, and a linear fit was performed. The LM/PI photothermal actuator responds rapidly, the LM/PI-8% photoactuator bends 60.161 in 2.75 s and the bending speed reaches 21.891 s À1 , which exceeds that of most of the reported photoactuators, [39][40][41][42][43][44][45][46][47][48][49][50][51] as shown in Fig. 5g and h.…”

Cooperative Photochemical Reaction Kinetics in Organic Molecular Crystals

“…Optical spectroscopy (absorption and fluorescence) has been widely used to monitor different chemical species present during the reaction. Photodimerization reactions in particular are easy to monitor using this method because the loss of conjugation leads to large absorption shifts and fluorescence changes after irradiation [19,57,58] . Other spectroscopies that are sensitive to the chemical environment can provide more detailed information.…”