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, H-1 NMR, C-13 NMR, MS 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(-50) cm(4) s photon(-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. (C) 2011 Elsevier Ltd. All rights reserved.