A Luminescent Stable Triarylmethyl Diradical with an Axially Chiral Spacer
Yohei Hattori, Ryota Matsuoka, Atsumi Baba, Shun Yoshida, Mihoko Yamada, Ryo Fujita, Daiya Suzuki, Yoshitane Imai, Kingo Uchida, Tetsuro Kusamoto, Gwénaël Rapenne, Tsuyoshi Kawai
Abstract
Two units of a highly stable luminescent triarylmethyl radical (PyBTM) were bridged using a chiral octahydrobinaphthyl moiety, resulting in a diradical with sufficient stability to enable the measurement of its chiroptical properties. To synthesize this diradical, a novel boronic ester radical precursor, αH-PyBTM-B(Epin), was designed. The use of this precursor significantly improved the yield and streamlined the preparation of stable luminescent radical-substituted molecules. The photoluminescence quantum yield (PLQY) of the diradical was measured to be 10 % in chloroform. Furthermore, both circular dichroism (CD) and circularly polarized luminescence (CPL) were successfully observed.