Author/Authors :
Nuding، نويسنده , , Guido and Zimmermann، نويسنده , , Edgar and Buss، نويسنده , , Volker، نويسنده ,
Abstract :
Bis[1,3-dimethyl-3,8-(trimethylen)-indolinyl]pentamethinium iodide (5) was synthesized by coupling rac 4a-methyl-2,3,4,4a-tetrahydro-1H-carbazole (3) with 1,1,3,3-tetraethoxypropane. The configuration of the dye is 2Z,8E,9E,10E,9′E,8′Z as shown by 1H NMR spectroscopy. Starting with the enantiomerically pure carbazole (95% e.e.) the optically active pentamethine 5a was obtained in 84% optical yield. The CD absorption of 5a at 653 nm indicates a significant helical distortion of the chromophore.
