Borocyclic Radicals Prepared from Orthoquinone-Containing Polycyclic Aromatics by Photoirradiation

Kazuki Urakawa; Yurie Yatsuoka; Yuta Kawabata; Hyuma Masu; Masaki Matsuda; Hayato Ishikawa

doi:10.1021/acs.joc.1c02283

Borocyclic Radicals Prepared from Orthoquinone-Containing Polycyclic Aromatics by Photoirradiation

J Org Chem. 2022 Mar 4;87(5):3647-3651. doi: 10.1021/acs.joc.1c02283. Epub 2022 Jan 18.

Authors

Kazuki Urakawa¹, Yurie Yatsuoka¹, Yuta Kawabata¹, Hyuma Masu², Masaki Matsuda³, Hayato Ishikawa⁴

Affiliations

¹ Division of Organic Chemistry, Department of Chemistry, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
² Center for Analytical Instrumentation, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan.
³ Division of Physical Chemistry, Department of Chemistry, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
⁴ Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan.

PMID: 35041408
DOI: 10.1021/acs.joc.1c02283

Abstract

Borocyclic radicals with highly conjugated aromatics were generated from orthoquinone-containing polycyclic aromatic compounds by trapping the photoinduced triplet state with simple boron halide under irradiation with light of appropriate wavelength. The picene-based borocyclic radical was remarkably stable when stored at 23 °C in a desiccator for over 1 year. The crystal structure of this stable radical had a stacking structure of a planar π-conjugated system, and the electrical conductivity was higher than those of ordinary organic radical systems.