1,4-Azaborine as a controller of triplet energy, exciton distribution, and aromaticity in [6]cycloparaphenylenes

Abstract

Cycloparaphenylenes (CPPs) have attracted the attention of researchers in various fields because of their unique properties, but studies and applications on host materials in the optoelectronics field are lacking. We undertook preliminary exploration and finally selected 1,4-azaborine and [6]CPP as the basic building blocks to construct a series of BN-[6]CPP hybrids. BN-[6]CPPs with various triplet energies (E_T = 1.66–3.52 eV) could be the potential hosts in full-color phosphorescent organic light-emitting diodes (OLEDs). DFT/TDA-DFT calculations showed that introduction of 1,4-azaborine rings at different positions of the [6]CPP hoop could efficiently control delocalization (localization) of triplet excitons and T₁-state aromaticity (non-aromaticity), and thus varied with the E_T. This work provides not only an efficient strategy for realizing E_T controllability for CPP-based materials by chemical modification of CPP frameworks, but also theoretical guidance for the design and prediction of novel hoop-shaped materials with high E_T in the organic optoelectronics field.