Inside Back Cover: Wurster’s Blue-type Cation Radicals Framed in a 5,10-Dihydrobenzo[a]indolo[2,3-c]carbazole (BIC) Skeleton: Dual Electrochromism with Drastic Changes in UV/Vis/NIR and Fluorescence (Chem. Asian J. 7/2014)

Abstract

Electrochromism The tribenzo analogue of Wurster′s Blue (WB) has a planar disk-like geometry and resembles Trillium kamtchaticum, the symbol flower of Hokkaido University (see the Inside Back Cover), where the molecule was designed by Takanori Suzuki et al. as a dual electrochromic system exhibiting drastic changes in the UV/Vis/NIR and fluorescence spectra. In collaboration with Hiroaki Ohno′s group at Kyoto University, the precursor diamine, 5,10-dihydrobenzo[a]indolo[2,3-b]carbazole (BIC), was synthesized by a gold(I)-catalyzed cascade cyclization as a key step. The precursor was then transformed into the stable cation radical characterized as a π-extended WB-type species by ESR. The X-ray analyses on both neutral and cationic states showed paraquinoid-type bond alternation upon oxidation. For more details, see the Full Paper on page 1841 ff.