The Tetrahydro Diazepine And Iso Quinoline (thai) And Dihydro-pyrrole And Tetrahydroisoquinoline Quinoline (thi) Light Induced Discoloration Of The Synthesis And Properties Of Compounds

Photochromism, one of the most striking phenomena of photochemistry, which involves light-induced reversible transformation of a molecule between two states with different distinguishable absorption spectra, has received great attention in recent years. Among the many photochromic systems, which reversibly inter-converted between distinct forms by irradiation, photochromic tetrahydroindolizines had received particular attention owing to their remarkable photofatigue-resistance and wide broad photochromic properties. Reversible coloration and bleaching upon wavelength-controlled illumination of photochromic tetrahydroindolizines are very desirable characteristics for optical switches, biological sensors, optical information storage and authentication systems.Recently, Duerr H. et al. reported on the synthesis of two novel reversible photochromic systems the tetrahydroazepinoisoquinoline (THAI) and the tetrahydroisoquinoline (THI). Two maxima could be detected (measured by ns excitation at 347.5nm on ruby laser flash photolysis) in the transient absorption spectra of dicyano-substituted tetrahydroazepinoisoquinoline (THAI). The lifetime of the tetrahydroisoquinoline (THI) was obtained without any further researches in photochromic properties. The decay of exited dicarboxylic ester- substituted THAIs could not be measured. They attribute such phenomena to apparatus limitation.In order to study the photophysical process (the photoinduced ring-opening reaction) of tetrahydroazepinoisoquinoline (THAI) and tetrahydroisoquinoline (THI) in detail, a series of novel dicarboxylic ester substituted THAIs and new THIs have been synthesized by changing substituents in dihydroisoquinolines 1 and spirocyclopropenes 2 . The structure of these products was confirmed by IR, H NMR, 13C NMR, MS, HRMS. Definite structure of new THAIs and THIs were elucidated by X-ray analysis.Three biphotochromic molecules containing both a spirooxazine(or spiropyran) and a 1,8a-dihydroindoline moieties and one containing two 1,8a-dihydroindoline moieties lined trough vinylene bridge were designed and investigated.Laser flash photolysis experiments were performed using an excimer laser which provided 308nm(XeCl) pulse with a duration 20 ns here based on the analysis of the...