Planar and Helical Dinaphthophenazines

Abstract

In this study, we report the synthesis of a series of planar and helical dinaphthophenazines by cyclocondensation reactions between the newly developed 9,10-bis((triisopropylsilyl)ethynyl)anthracene-1,2-dione and different diamines. Their optoelectronic and electrochemical properties are studied by ultraviolet–visible (UV–vis) spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and density functional theory calculations.

A Strategy to Design Substituted Tetraamino-Phenazine Dyes and Access to an NIR-Absorbing Benzoquinonediimine-Fused Quinoxaline

“…Phenazines are tricyclic dibenzannulated heterocycles containing a central pyrazine core, well-known as naturally occurring substances, biologically active species, and dyestuffs (e.g., safranine, neutral red). − Beyond being popular chromophores, their unique optical and electrochemical properties allowed for their use as chemosensors , or photocatalysts for photopolymerization or cross-coupling reactions. − In organic electronics, phenazines have demonstrated their potential as low-bandgap semiconductors in solar cells , and as electroactive compounds in batteries. , They have also found a particular interest for the elaboration of organic light-emitting diodes (OLEDs), notably due to the rigidity and electron-withdrawing character of the phenazine core, which is beneficial for designing thermally activated delayed fluorescent dyes, as exemplified with the recent report of sterically hindered tetrabenzophenazine-phenoxazines that afforded efficient orange-red OLEDs . Furthermore, the straightforward synthesis of simple phenazines through polycondensation reactions enables the preparation of various π-extended planar chromophores derived from azaacenes, and this motif can be found in many polyaromatic heterocyclic nanographenes, two-dimensional conjugated macrocycles, 3D porous architectures, − as well as helicoidal derivatives. , …”

“…17 Furthermore, the straightforward synthesis of simple phenazines through polycondensation reactions enables the preparation of various π-extended planar chromophores derived from azaacenes, and this motif can be found in many polyaromatic heterocyclic nanographenes, 18 two-dimensional conjugated macrocycles, 19 3D porous architectures, [20][21][22] as well as helicoidal derivatives. 23,24 Seminal strategies to access phenazine dyes are based on the condensation of nitrobenzene and aniline derivatives at high temperature in the presence of base (Wohl-Aue procedure), the ring enlargement of benzofuran-1-oxide (Beirut reaction) and the condensation of 1,2-diaminobenzenes with various diones or o-benzoquinones. 25 Other notable approaches rely on the reaction of o-aminobenzophenones and cyclohexanones, 26 or on several catalytic processes including straightforward metal-catalyzed intramolecular cyclization or N-arylation.…”