Perhalogenated Tetraazaperopyrenes and Their Corresponding Mono- and Dianions

Abstract

Chlorination and bromination of 2,9-perfluoropropyl-substituted tetraazaperopyrenes (TAPPs) under forcing conditions resulted in fully core-halogenated TAPP derivatives, devoid of hydrogen atoms at the polycyclic aromatic core. The octahalogenation stabilized the reduced mono- and dianionic compounds sufficiently to allow for their characterization. The additional ortho-chlorination led to an improvement of the electron mobility compared to the bay-substituted tetrachloro-TAPP when employed as an n-channel semiconductor in thin-film transistors.

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

“…We systematically investigated the chemistry and properties of tetraazaperopyrenes (TAPP) as electron accepting functional dyes which were found to possess similar electrochemical and photo physical properties but distinctly different reactivity compared to the extensively studied perylenediimides (PDIs). [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ] In contrast to the PDIs, the electron accepting character of the TAPP derivatives arises from the fourfold isosteric replacement [CH→N] and not the addition of strong electron withdrawing groups like the carboximide substituents. [48] In this way, the strong electron accepting behavior and the resulting electronic materials properties are introduced into the aromatic core without changing the molecular shape.…”

“…Additionally, we recently developed a synthetic approach to functionalize the bay ‐position which made the bay chlorinated and perhalogenated TAPPs accessible,[ 48 , 49 , 50 ] while the planarity of the aromatic core is lost due to the steric pressure. Finally, perhalogenation of the TAPP core (Scheme 1 ) leads to further reduction of the LUMO energy and improved electron acceptor properties, rendering radical anions and dianionic species isolable.…”

Antiaromaticity-promoted radical anion stability in α-vinyl heterocyclics

“…23 Previous reports have shown that introducing nitrogen atoms or electron-withdrawing groups into the polycyclic aromatic hydrocarbon (PAH) aids in the formation of stable radical anions. [24][25][26][27][28][29][30][31][32] It is well known that spin delocalization can improve the stability of radical anions, particularly for large planar structures, such as PAHs, due to the conjugation effects. In addition, the dimerization reaction of two bowlshaped PAH monoanion radicals was first reported in 2018 by the Petrukhina and Rogachev groups.…”

Unraveling the electrochemical and spectroscopic properties of neutral and negatively charged perylene tetraethylesters

“…Hence, a firm understanding of the reduced species of perylene imides and esters is necessary, since both types of compounds are either commonly used as electron transporting layers (PDIs) or electron acceptors or have the potential of becoming widely used in the future (PEs), respectively. In the case of PDIs, studies have been performed recently on the reduced states of several imide derivatives 47 – 49 . However, to the best of our knowledge similar investigations into their ester counterparts have not yet been reported.…”

“…This observation appears to also hold for quantum chemical studies of charged perylene esters. In case of the imides, results for the spectroscopic properties of the monoanionic and dianionic species from such calculations have been published recently 48 , 49 . These theoretical investigations are based on density functional theory (DFT) and mainly employed the B3LYP functional with an exception being the calculation of interconversion energies, for which the PBE0 functional was used.…”