Power of light – Functional complexes based on azobenzene molecules

Thermochromic Behavior of Azobenzene‐based Coordination Polymer with Reversible Breathing Process

“…And the PXRD profiles at the selected temperatures are almost the same between 25 and 60 °C for 1 and confirms that the dehydrated sample 1 maintains the same framework as the original hydrated complex 1 during such a process (Figure ). Besides, we also measured the photochromic of 1 , no obvious color change was observed between before and after irradiation, which might be attributed to the strong localized energy of crystal lattice of 1 restricts the azobenzene isomerization effect, compare with the traditional azobenzene‐derivates MOFs . According to the above results and discussion, we suppose that the reversible thermochromic behavior might be ascribed to the change of the coordination environment of Zn 2+ ions with the loss of the lattice water and terminal water molecules at different temperatures .…”

“…Interestingly, the crystals of 1 keep crystalline‐phase even all the lattice water and terminally coordinated water molecules have been removed completely by heating at 270 °C or vacuum freeze drying for 24 hrs, which could be confirmed by variable‐temperature powder X‐ray diffraction (PXRD). As shown in Figure , compared with simulated pattern, there are slight shift for the powder data of the sample at different temperatures, which might be attributed to the preferred orientation or the lattice distortion with the temperature change . The PXRD profiles at the selected temperatures are almost the same between 25 °C and 270 °C for 1 (Figure S3).…”

“…Given these aspects, it is crucial for a suitable ligand to help in fine‐tuning the physicochemical properties of MOFs. Recently, a family of chemically designed chromic materials with isomerization units, such as azobenzene, spirooxazines, Schiff bases and stilbene, and relative derivatives have been suggested as promising stimuli‐responsive materials. Particularly, functional materials incorporating azobenzene derivatives are very promising candidates due to their unique reversible isomerization effect and high sensitivity.…”

Configurational Selection in Azobenzene‐Based Supramolecular Systems Through Dual‐Stimuli Processes

“…Beside the works describing the complexation with alkaline cations, a large number of studies also demonstrated that transition metals such as palladium, zinc, iron, nickel, copper, iridium, etc may strongly perturb the photoisomerization equilibrium of the azobenzene switch . The transition metal ion can directly bind to the nitrogen atoms of the N=N bond or to a dedicated functional group connected to the azobenzene moiety, and it may influence the switching process with different mechanisms.…”

Metal‐Containing Polymers as Light‐Emitting and Light‐Responsive Materials and Beyond

“…[29][30][31] Amongst all the different classes of photoswitches, such as stilbenes, coumarins, diarylethenes and azobenzenes, the last mentioned holds al eading position because of the possibility to reversibly undergo photo-isomerisation between at hermodynamically stable trans form and an out-ofequilibrium cis conformer.I ns uch systems, relative stability of the energy levels, and thus quantum yield of the photo-isomerisation processes and excited state lifetime, can be varied by molecular design.M oreover,w avelength of the excitation input promoting isomerisation can be easily modulated by substituent effect. [32][33][34] Integration of such am oiety into ap eriodic, rigida nd supramolecularly organised array may allow formation of materials in which light-triggered geometrical changes at them olecular level are translated to macroscopic scale. We have recently employed such approach for the preparation of the first examples of light-powered soft actuators based on metallo-supramolecular gels.…”