Two-photon absorption dyes with thiophene as [pi] electron bridge: Synthesis, photophysical properties and optical data storage

Four novel dyes are prepared by thiophene as [pi] bridge between carbazole central core and other terminal groups by Suzuki and Heck coupling reactions. These dyes are fully characterized by IR, super(1H NMR, ) super(1)3C NMR, and elemental analysis. Linear absorption, single- and two-photon excited fluorescence in various solvents are experimentally investigated. The calculated two-photon absorption cross sections of 9-Hexyl-3,6-di((5-phenyl)-2-thienyl)carbazole ( 1), 9-Hexyl-3,6-di((5-thienyl)-2-thienyl)carbazole ( 2), 9-Hexyl-3,6-di((5-p-vinylpyridyl)-2-thienyl)-carbazole ( 3) and 9-Hexyl-3,6-di-((5-o-vinylpyridyl)-2-thienyl)carbazole ( 4) for the lowest excited state are 537.84, 550.76, 1292.95 and 1340.40 x 10 super(-50 cm) super(4) s photon super(-1, respectively. Calculated and experimental data have shown that thiophene as [pi] electron bridge improves the two-photon absorption cross sections greatly. Two-photon optical data recording experiments have been carried out at 820 nm laser radiation.)