Promising Molecules for Optoelectronic Applications: Synthesis of 5,10‐Dihydrobenzo[a]indolo[2,3‐c]carbazoles by Scholl Reaction of 1,2‐Bis(indol‐2‐yl)benzenes

Abstract

Only a few straightforward procedures for the preparation of indolo[2,3‐c]carbazoles are known, despite promising features for material applications. Herein we present a convenient synthesis of 5,10‐dihydrobenzo[a]indolo[2,3‐c]carbazoles using an oxidative cyclization of 1,2‐bis(1H‐indol‐2‐yl)benzenes prepared from readily accessible starting materials. Functionalization through electrophilic aromatic substitution reactions and palladium‐catalyzed cross‐coupling reactions were investigated, which lead to the isolation of new functionalized 5,10‐dihydrobenzo[a]indolo[2,3‐c]carbazoles, whose steady state electronic spectroscopy has been examined.

Carbocatalytic Oxidative Dehydrogenative Couplings of (Hetero)Aryls by Oxidized Multi‐Walled Carbon Nanotubes in Liquid Phase

“…Interestingly, 3c required av ery long reaction time and after sixd ays, 29 %y ield was obtained together with 60 %o f unreacteds tartingm aterial. To our pleasure, 4d,w hich has been indicated as potential substructure for p-type organic semiconductors [33] and promising framework for optoelectronic applications, [34] was obtained in an 84 %y ield. Similarly, 4f,a substructure found in molecules with interesting chiroptical properties fora pplicationss uch as,f or example, spintronic devices, [35] was obtained in 82 %yield.…”

5,10-Dihydrobenzo[a]indolo[2,3-c]carbazoles as Novel OLED Emitters

“…This suggests that, in agreement with the DFT calculations, the conjugation is extended over these moieties in 4 . In the previous paper, we inferred by comparing the steady-state absorption and emission spectra in toluene and ACN that the excitation is localized on the benzindolocarbazole moiety for 1 , 2 , and 3 , whereas for 4 a CT character was implied, and that in 1 , 2 , 3 , and 4 the N substituents are not involved in the excitation. These conclusions are confirmed by the theoretical calculations and electrochemical results (vide supra).…”

“…In Table S2, the corresponding figures of merit for all solvents are collected. As the spectra are discussed more in detail elsewhere, the most important conclusions will be briefly repeated here. In the absorption spectra of 1 , 2 , and 3 , three different transitions can be distinguished, each possessing a vibrational fine structure, which correspond with the S 0 → S 1 transition around 400 nm, the S 0 → S 2 transition around 340 nm, and the S 0 → S 3 transition around 310 nm.…”

“…The indolo­[2,3- c ]­carbazole isomers, however, were not yet fully investigated but appear to be interesting for OLED applications . Recently, we reported the synthesis of new promising electroluminescent materials: 5,10-dihydrobenzo­[ a ]­indolo­[2,3- c ]­carbazole derivatives . To design an efficient OLED device, it is of paramount importance that the relation between the structure and the optoelectronic properties is well-understood.…”

Enhancing Charge Transfer and Photoelectric Characteristics for Organic Solar Cells

“…As the filling material of the photoactive layer, the sensitizer can be divided into two types: metal sensitizer and nonmetal sensitizer. Nonmetallic sensitizer and polymers have the advantages of nonpollution, stability and well performance, which can be used as a potential candidate in the field of optoelectronics [4,5].…”