Stable <scp>Boron‐Containing Blue‐Photoluminescent</scp> Radicals

Abstract

Main observation and conclusion It is highly urgent to develop synthetic strategies to make new category of stable luminescent radicals with desired emission wavelength. In this study, we have isolated two dioxoborocyclic radicals (3 and 4) by a direct synthetic route. They were characterized by UV, EPR spectroscopy and SQUID measurements. Their structures were obtained by single‐crystal X‐ray diffraction. Both radicals produce blue‐photoluminescence (458 nm for 3 and 478 nm for 4) by radiative decay from higher excited states (D 2 /D 3 ) to the ground state (D 0 ) based on theoretical calculation, breaking Kasha rule. The work records a new kind of radical emitters and the first stable radicals with blue emission bands.