Photochromism of dihydroindolizines. Part II-Synthesis and photophysical properties of new photochromic IR-sensitive photoswitchable substituted fluorene-9′-styrylquinolinedihydroindolizines
作者:Saleh Abdel-Mgeed Ahmed
DOI:10.1002/poc.509
日期:2002.7
Twenty-nine new photochromic 2,4,7-substituted fluorene-9′-styrylquinolinedihydroindolizines (DHIs) 4a–χ were prepared in 45–75% yield via nucleophilic addition of 4-styrylquinolines 2a–k to substituted spirocyclopropenes 1a–c. The absorption maxima (λmax) of the colored betaines 3a–χ were detected by flash photolysis measurements. All betaines 3a–χ showed two absorption maxima, one in the visible
New mono-(5a-t, w) and biphotochromic (5u, v) 9'-styrylquinolinespirodihydroindolizines (DHIs) with IR-absorbing colored forms (4) were prepared. The conformation and configuration of these new DHIs were investigated by NMR studies and the structure was proved by x-ray analysis. The kinetics of the fast cyclizing process of betaine 4 to DI-II 5 takes place in the millisecond range and were studied by flash photolysis. The absorption bands of the betaines 4 were recorded at low temperature by FT-UV/VIS/near-IR spectroscopy. Large solvent effects on the absorption maxima of betaines 4 were observed. Copyright (C) 2000 John Wiley & Sons, Ltd.
Photochromism of dihydroindolizines part VII: multiaddressable photophysical properties of new photochromic dihydroindolizines bearing substituted benzo[i]phenanthridine as a fluorescing moiety
作者:Saleh Abdel-Mgeed Ahmed
DOI:10.1002/poc.1209
日期:2007.8
to green–blue colored betaines 7a-p after cooling with liquid nitrogen. The kinetics of the fast bleaching process of betaines 7a-p to DHIs 8a-p, studied by flash photolysis as well as low temperature FT-UV/VIS, were found to take place in the millisecond range (432–2675 ms) in dichloromethane solution and fitted well a first-order thermal back reaction. The fluorescence spectra as well as the fluorescence