877754-50-2Relevant academic research and scientific papers
Photochromic spirotetrahydroazafluorenes: Part IV. First trapping of novel type of c/s-fixed photochromes based on pyridazinopyrrolo[1,2-b]isoquinoline
Ahmed, Saleh Abdel-Mgeed
, p. 295 - 300 (2007/10/03)
Seven novel 2′,3′-diacetyl spirotertrahydroindolizines (THIs) 3a-g were synthesized in low yield via the nucleophilic addition of the substituted isoquinoline derivatives 2a-g to diacetyl spirocyclopropene 1 in dry ether at -20°C under nitrogen atmosphere
Photochromic spirotetrahydroazafluorenes: Part V. Why photochromic molecules with rigid region B exhibiting extremely fast bleaching process?
Ahmed, Saleh A.,Duerr, Heinz
, p. 275/[575]-280/[580] (2007/10/03)
Spirotetrahydroindolizines (THIs) 1a-g and Spirotetrahydroazafluorenes (THF) 2a-g were previously synthesized. The high reaction rate of the thermal 1,5-electro-cyclization results in the half-lives of the colored betaines 2′a-g range from 3.9 to 5.4 ns, thus showing the existence of the shortest lived colored form observed so far for pyrazoline based photochromes. However, laser flash spectroscopy was successfully used for the determination of both the half-life and absorption maxima of the colored betaines 2′a-g. Time resolved transient spectroscopy shows the geometry of the betaines 2′a-g to be related to one of the two detectable intermediates 1′a-g or 1″a-g.
