Synthesis, Opto‐electrochemical and Theoretical Investigation of Pyrazino[2, 3‐b]phenazine Amines for Organic Electronics

Abstract

A series of five novel donor–acceptor molecules based on tetraazatetracene skeleton containing electron deficient pyrazino[2, 3‐b]phenazine core as acceptor and electron rich triarylamines as donor moiety have been synthesized by Buchwald−Hartwig coupling amination reaction and fully characterized. The synthesized molecules were studied for their optoelectronic properties. Absorption spectra of all the compounds showed intramolecular charge transfer (ICT) transitions in the range of 430−502 nm. All compounds emit in green−red region with emission maxima in the range of 491−639 nm on excitation at their respective ICT absorption maxima. The HOMO and LUMO energy level were found in the range of –5.40 to –5.66 eV and –3.69 to –3.84 eV respectively as calculated by cyclic voltammetry (CV). Theoretical studies were also carried out by using TD−DFT calculations. On the basis of HOMO and LUMO energy level, synthesized compounds could act as ambipolar materials in organic electronics.

Asymmetric N-heteroacene tetracene analogues as potential n-type semiconductors

“…37 We expect these radicals are symptomatic of intermolecular, rather than intramolecular, charge transfer due to the reasonably symmetrical nature of the LUMO orbitals. Typically, intramolecular charge transfer operates most effectively with distinct acceptor:donor molecular domains, 39 which are absent here.…”

Fluorescent indolo[2,3-b]quinoxalin-2-yl(phenyl)methanone dyes: photophysical, AIE activity, electrochemical, and theoretical studies

“…Though there is no general guideline to obtain air-stable n-type materials, according to the literature LUMO level can be lowered through the introduction of electron-withdrawing groups -F, -CN, -Cl, -NO 2, -COOH, -CF 3 and per uorinated alkyl chain in p-type materials; An alternative approach is the incorporation of electronegative heteroatoms like N or S to acceptor core of D-A system can promote injection and transport of electrons in resulting molecules [16]. Previously, we designed and reported different D-A based molecules comprised of donor moieties like aromatic amines (triarylamine/diarylamine/ aryl), heterocyclic amine (carbazole/phenothiazine), and acceptor moieties quinoxaline [17][18][19][20][21], indoloquinoxaline [22,23], phenazine [24][25][26], pyrido-pyrazine [27,28], pyrazino-phenazines [29] acridone [30], and anthraquinone [31], to obtain a broad range of emission, solvato uorochromism, AIE, TADF, hole/electron/bipolar charge transport for their application in organic electronics. Indoloquinoxaline (IQ) is also one of the important classes of N-containing heterocyclic compounds.…”