Unveiling a New Aspect of Simple Arylboronic Esters: Long-Lived Room-Temperature Phosphorescence from Heavy-Atom-Free Molecules

作者：Shoji, Yoshiaki; Ikabata, Yasuhiro; Wang, Qi; Nemoto, Daisuke; Sakamoto, Atsushi; Tanaka, Naoki; Seino, Junji; Nakai, Hiromi^*; Fukushima, Takanori^*

来源：Journal of the American Chemical Society, 2017, 139(7): 2728-2733.

DOI：10.1021/jacs.6b11984

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Arylboronic esters can be used as versatile reagents in organic synthesis, as represented by Suzuki Miyaura cross-coupling. Here we report a serendipitous finding that simple arylboronic esters are phosphorescent in the solid state at room temperature with a lifetime on the order of several seconds. The phosphorescence properties of arylboronic esters are remarkable in light of the general notion that phosphorescent organic molecules require heavy atoms and/or carbonyl groups for the efficient generation of a triplet excited state. Theoretical calculations on phenylboronic acid pinacol ester indicated that this molecule undergoes an out-of-plane distortion at the (pinacol)B-C-ipso moiety in the T-1 excited state, which is responsible for its phosphorescence. A compound survey with 19 arylboron compounds suggested that the phosphorescence properties might be determined by solid-state molecular packing rather than by the patterns and numbers of boron substituents on the aryl units. The present finding may update the general notion of phosphorescent organic molecules.

• 出版日期2017-2-22