Synthesis, Characterization, and Crystal Structure of One Novel Indolo[3,2-b] carbazole Derivative

Indolocarbazole derivatives have been reported to be promising organic semiconductor candidates and electroluminescent (EL) materials. One novel indolocarbazole derivative, 2,8-acetyl-5,11-dihexy1-6,12 -(di-p-toly1)-5,11-indolo [3,2-b] carb azo le (YK4), has been synthesized, and its crystal structure has also been carefully studied. YK4 is triclinic, space groups P (1) over bar with a = 9.409(5), b = 13.974(5), c = 15.488(5) angstrom, alpha = 90.281(5), beta = 105.456(5), gamma = 93.728(5)degrees, M-r = 688.94, V= 1958.1(14) angstrom(3), Z = 2, D-c = 1.168 g/cm(-3), mu = 0.070 mm(-1), F(000) = 740, R-int = 0.0475, R (I> 2 sigma(I)) = 0.1146, wR (I> 2 sigma(I)) = 0.2186, R (all data) = 0.2192 and wR (all data) = 0.2701. Like other indolo[3, 2-b]carbazole derivatives which were introduced in the 5- and 11-positions, the intermolecular short contacts are localized between the pendant groups and acetyl groups of the neighboring indolocarbazole molecules. The molecule of YK4 possesses poor face-to-face pi-pi stacking between two adjacent molecules in the crystal. The calculated bond lengths and bond angles of YK4 also proved the result of crystallography.