An Air- and Water-Stable B4N4-Heteropentalene Serving as a Host Material for a Phosphorescent OLED

Junki Kashida, Yoshiaki Shoji*, Yasuhiro Ikabata, Hideo Taka, Hayato Sakai, Taku Hasobe, Hiromi Nakai, Takanori Fukushima

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Replacement of the carbon–carbon bonds of antiaromatic compounds with polar boron–nitrogen bonds often provides isoelectronic BN compounds with excellent thermodynamic stability and interesting photophysical properties. By this element-substitution strategy, we synthesized a new B4N4-heteropentalene derivative, 1, which is fully substituted with mesityl groups. Owing to kinetic protection by the sterically bulky substituents, 1 is remarkably stable toward air and even water. Single-crystal X-ray analysis of 1 revealed the bonding characteristics of the B4N4-heteropentalene structure. In a glassy matrix, 1 emitted short-wavelength phosphorescence with an onset at 350 nm, indicating that the triplet energy is substantially high. DFT calculations reasonably explained the ground- and excited-state electronic structures of 1 as well as its emission properties. Motivated by the high-energy triplet state of 1, we used it as a host material to fabricate a phosphorescent organic light-emitting diode with an external quantum efficiency of 15 %.

Original languageEnglish
JournalAngewandte Chemie - International Edition
DOIs
Publication statusAccepted/In press - 2021

Keywords

  • boron
  • heterocycles
  • luminescence
  • main-group elements
  • phosphorescence

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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