A Hexagonal Shape‐Persistent Nanobelt of Elongated Rhombic Symmetry with Orthogonal π‐Planes by a One‐Pot Reaction

Abstract

Triptycenes with their predefined D 3h -symmetry are excellent molecular building blocks to construct shape-persistent nanobelts having π-orbitals orthogonal to the ring plane. However, up to now, there are only a very few examples of fused and rigid iptycene nanobelts synthesized in several consecutive steps in overall yields below 1 %. Here we present the simple one-step one-pot approach to an iptycene nanobelt, which forms in > 2 % and can readily be isolated from the polymeric by-product by gel-permeation chromatography.

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. , …”

“…14,15 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, 16 as exemplified with the recent report of sterically hindered tetrabenzophenazinephenoxazines that afforded efficient orange-red OLEDs. 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.…”