Synthesis and Characterization of Novel 1,4-Bis(carbazolyl)benzene Derivatives with Blue-Violet Two-Photon-Excited Fluorescence

Abstract

Novel fluorescent two-photon absorption molecules containing bis(carbazolyl)benzene as the central unit and phenylethynyl moieties as peripheral groups (Cz-Ps) are synthesized and characterized. In these molecules, two carbazolyl moieties are linked with benzene at the 9-position and synthesized by a concise process involving nucleophilic substitution between the cyclopentadienyliron complexes of dichloroarenes and phenylethynyl carbazole, followed by photolysis. The optimal structures of Cz-Ps reveal that two carbazolyl rings linked by a benzene ring are not planar. This feature prevents the electron conjugation of the molecule from extending throughout the whole molecule and allows Cz-Ps to realize blue-violet emissions and high fluorescence quantum yield. With increasing number of conjugated phenylacetylene structures in Cz-Ps, the maximal absorption and emission peaks were red-shifted. The quadrupolar compound DMoCz-P shows strong one-photon and two-photon activities. The resulting molecules are also ...