Synthesis and characterization of novel conjugated bisindenocarbazoles

We present the synthesis of five new bisindenocarbazoles with different alkyl substituents. The synthesis starts from 2,7-dibromocarbazole and leads to the bisindenocarbazoles 6-10 in five steps with an overall yield of about 50%. By substitution of the core with different alkyl chains in the last step of the synthesis, the morphology of the bisindenocarbazoles can be varied from crystalline materials to molecular glasses. The bisindenocarbazoles are electrochemically stable and exhibit a strong, saturated blue emission with a quantum yield of 63% in solution.