Three functional Cd(II) coordination polymers constructed by the thiazolothiazole extended viologen ligand

A Viologen Derivative Transition from Photosilence to Sensitive Photochromism through Ion Exchange

“…Time-dependent solid UV–vis spectra show that its reflectance at 500–700 nm decreases greatly after irradiating for 5 s and continues to gradually decrease with the increase in time (Figure b), corresponding to the characteristic peak of viologen radicals, , indicating the generation of 4PV +• radicals under UV irradiation. The 4PV·2B­(Ph) 4 powder can show an obvious photoinduced color change within 5 s and reach the color saturation state in about 30 s, which is more sensitive when compared with other viologen derivatives reported recently (their photochromic responsiveness timescales: 15 s to 5 min). − To investigate the sensitivity of 4PV·2B­(Ph) 4 for UV light detection application, power-dependent photochromism has also been performed (Figure c). It can be found that the 4PV·2B­(Ph) 4 powder shows an obvious color change with the increase in light intensity (power ranging from 0 to 100 W; each irradiation time is 5 s).…”

Crystal structures and stimuli-responsive properties for three novel D–A type salicylhydrazide–viologen compounds with free radical properties under ambient conditions

“…The choice of electron-donating groups mainly lies on the π-conjugated groups, 25,26 benzenecarboxylic groups 27–31 or electron-enriched polyoxometalates (in short POMs). 32–36 However, the π-conjugated groups are always polycyclic aromatic whose synthesis requires a tough organic procedure.…”