Towards Nitrogen‐Rich N‐Heteropolycycles: Synthesis of Octaazaperopyrenes (OAPP)

Abstract

Ortho substituted octaazaperopyrenes (OAPPs) are a new class of functional dyes characterized by their strong electron‐accepting behavior. Herein, the synthesis, as well as the electrochemical and photo physical properties of an OAPP dye, is reported. The OAPP target was prepared via selective nucleophilic substitution at the peri position of a bay chlorinated tetraazaperylene by introduction of four amino‐substituents. The resulting tetraminoperylene was reacted with different acyl chlorides and anhydrides to give the twisted bay chlorinated OAPP derivatives which were isolated in their reduced dihydro‐form. The OAPP target could be obtained via a palladium catalyzed dehalogenation and a subsequent oxidation. The eightfold isosteric [CH→N] replacement within the peropyrene core structure results in a large decrease of the frontier orbital energies, rendering the target compound a potent oxidant while preserving the planarity of the aromatic core. The radical anion was obtained by reduction of the OAPP with KC8 and characterized by EPR spectroscopy. A general discussion of the number and location of [CH→N] replacements in peropyrene structures and their frontier orbital energies is provided.

Peri‐Decoration of a Tetraazaperylene with Urea Units: Chiral Octaazaperopyrenedioxides (OAPPDOs) and Their Optical and Chiroptical Properties

“…[37][38][39][40][41][42] Recently, we have begun to extend the construction principle outlined above to dyes based on a tetraazaperylene core (Scheme 1, bottom), thus reducing the frontier orbital energies by [CH!N] replacement within the central aromatic polycycle. [43] Further modification following the synthetic routes to the previously studied TAPPs gave access to the nitrogen rich, strongly electron-accepting octaazaperopyrenes (OAPPs) for which a first assessment of their properties has been reported. [43] Based on the tetraazaperylene core we have now added Nsubstituted urea units in the peri positions, thus generating a periphery which is complementary to the dicarboximido termini in the PDIs.…”

“…[43] Further modification following the synthetic routes to the previously studied TAPPs gave access to the nitrogen rich, strongly electron-accepting octaazaperopyrenes (OAPPs) for which a first assessment of their properties has been reported. [43] Based on the tetraazaperylene core we have now added Nsubstituted urea units in the peri positions, thus generating a periphery which is complementary to the dicarboximido termini in the PDIs. Similar to the latter, the combination of NHÀ and carbonyl functions allows the formation of intermolecular hydrogen bonds which ultimately is expected to lead to stable, tightly packed materials.…”

“…[39,[44][45][46][47] This new class of dyes may be viewed as formally derived from the recently reported octaazaperopyrenes by oxidation of the two axial CH units and is therefore referred to as octaazaperopyrenedioxides (OAPPDO). [43] Specifically, we report the synthesis of a bayhalogenated OAPPDO derivative which has offered the opportunity for further functionalization and, in particular, freezing in the twisted conformation of the polycyclic aromatic core. This has led to the isolation of helically chiral OAPPDO dyes.…”

“…Similar to the latter, the combination of NH− and carbonyl functions allows the formation of intermolecular hydrogen bonds which ultimately is expected to lead to stable, tightly packed materials [39,44–47] . This new class of dyes may be viewed as formally derived from the recently reported octaazaperopyrenes by oxidation of the two axial CH units and is therefore referred to as octaazaperopyrenedioxides (OAPPDO) [43] . Specifically, we report the synthesis of a bay‐halogenated OAPPDO derivative which has offered the opportunity for further functionalization and, in particular, freezing in the twisted conformation of the polycyclic aromatic core.…”

Versatile access to nitrogen-rich π-extended indolocarbazolesviaa Pictet–Spengler approach

“…Especially the isosteric replacement of CH moieties by nitro-gen atoms is used to alter molecule properties as frequently seen with azaacenes [25][26][27] and other compounds. [28][29][30][31] The influence of these replacements can be quite substantial. For example, the introduction of nitrogen atoms can lower the HOMO-LUMO (lowest unoccupied molecular orbital) energies in a fashion that enables to transform a typical electron donor into an acceptor, which allows the application as n-type semiconductor.…”