ascribed to an electrochemical local-cell mechanism and a chain reaction mechanism. Electron transfer stopped-flowstudy using a chemical oxidant successfully identified radicalcation intermediates of both closed- and open-ring isomers, involved in the oxidative cycloreversion process. The significantly long-lived radicalcation of open-ring isomer with the lifetime of 33 s takes part in the indirect
synthesized and their photochromic properties have been studied both in solution and in the crystalline state. The thiazolyl-substituted terarylenes displayed reversible photochromism in solution, with photocyclization quantum yields as high as 60 %, while a 4,5-dithienylthiazole derivative underwent photochromic reaction even in the single-crystal state, although a 4,5-dithiazolylthiazole (terthiazole) showed
Luminescent EuIII complex having photochromic ligand is synthesized, and its reversible control of the luminescent properties based on photochromic reaction was demonstrated.
合成了具有光致变色配体的发光EuIII配合物,并证明了其基于光致变色反应的发光性能的可逆控制。
Syntheses and photochromic properties of diaryl acenaphthylene derivatives
A series of diaryl acenaphthylenes has been synthesized, and their photochromic properties are studied both in solution and in the crystalline state. 2,4-Dimethyl-5-phenylthiophene derivative 1a showed no photochromic reaction, while 2-methyl-5-phenylthiophene derivative 2a and 5-methyl-2-phenylthiazol derivative 3a showed reversible photochromism in solution. Fluorescence spectrum of compound 3a changed
were determined from the kinetics analysis and by NMR titration and were found to be moderate for the colored form and veryweak for the colorless form. These results were interpreted considering the basicity of the molecules and the solvent effect on the acid strength. The structural consequences of the protonation on the ring-closed compound and on the entire ring-opening process were examined by