1592-72-9Relevant academic research and scientific papers
Fast (hetero)aryl-benzothiazolium ethenes photoswitches activated by visible-light at room temperature
Coelho, Paulo J.,Castro, M. Cidália R.,Raposo, M. Manuela M.
, p. 163 - 169 (2015/03/30)
A series of novel photochromic cationic stilbenes dyes bearing different aromatic systems were easily synthesized from (hetero)aromatic aldehydes. The photoisomerization of the double bond can be achieved through irradiation with ultraviolet or visible light, for few seconds, leading to the Z isomers that return much faster to the initial state than common stilbenes. Benzothiazolium dyes with electron donating substituents exhibited very fast thermal back reactions (1 s). Pyrrole-benzothiazolium dye showed a higher lifetime of the Z isomer, in different solvents, including water (0.45-7.1 min). This cationic diarylethene can be switched between the E-Z states using visible light, in few minutes at room temperature, with a noticeable change in the visible spectrum.
Photophysics, photochemistry and thermal stability of diarylethene-containing benzothiazolium species
El-Hendawy, Morad M.,Fayed, Tarek A.,Awad, Mohamed K.,English, Niall J.,Etaiw, Safaa Eldin H.,Zaki, Ahmed B.
, p. 20 - 31 (2015/01/30)
The photophysics, photochemistry and thermal stability of four 1-aryl-2-(N-methyl-2-benzothiazolium) ethene iodides (aryl: phenyl, 1-naphthyl, 9-phenanthryl and 9-anthryl) were studied. Although the absorption spectra are found to be hypsochromic-shifted, fluorescence spectra are bathochromic-shifted. The dipole moment in the relaxed excited state was found to be larger than that in the ground state. To investigate effects of N-methylation and the aryl-ring size, a detailed comparison was made between those in the present work (of charged compounds) and previous studies of their neutral analogues, with computed electron affinity and ionisation potentials serving to rationalise the experimentally observed bathochromic shifts in absorption and emission spectra. The kinetics of thermal isomerisation depend strongly on the nature of the aryl moiety and solvent; the larger the aryl ring, the slower the rate of isomerisation. The fastest isomerisation process was found to take place in MeOH. The anthryl derivative did not isomerize either by light- or heat-exposure, due to high energy barriers of rotation around the ethenic bond. Based on the significant blue-shift of the Z-isomer absorption maximum relative to that of the E-isomer, and the high percentage of Z-isomers in the photostationary state, these compounds may serve as potential promising candidates for optical data-storage applications.
