5,10-Dihydrobenzo[a]indolo[2,3-c]carbazole: A Highly Fluorescent Disk-shaped Electron Donor Exhibiting Dual UV–vis–NIR and Fluorescence Spectral Changes upon Electrolysis

Abstract

Abstract Through gold(I)-catalyzed cascade cyclization as a key step, the title electron donor was prepared, which adopts a planar geometry, as confirmed by an X-ray analysis. Due to 1,4-phenylenediamine moiety incorporated in the framework, it undergoes reversible one-electron oxidation. Upon electrolysis, it exhibited an electrochromic response in the UV–vis–NIR region, which was accompanied by a drastic change in the fluorescence spectrum since only the neutral donor is highly fluorescent.