TY - JOUR
T1 - Unveiling a New Aspect of Simple Arylboronic Esters
T2 - Long-Lived Room-Temperature Phosphorescence from Heavy-Atom-Free Molecules
AU - Shoji, Yoshiaki
AU - Ikabata, Yasuhiro
AU - Wang, Qi
AU - Nemoto, Daisuke
AU - Sakamoto, Atsushi
AU - Tanaka, Naoki
AU - Seino, Junji
AU - Nakai, Hiromi
AU - Fukushima, Takanori
N1 - Funding Information:
This work was supported by KAKENHI (Nos. 26102008 and 26708004) and Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials from the Ministry of Education, Culture, Sports Science and Technology of Japan (MEXT). The authors would like to thank Suzukakedai Materials Analysis Division, Technical Department Tokyo Institute of Technology, for their support with the elemental analysis and ICP-AES analysis. The authors would also like to acknowledge JASCO Corporation for determining the phosphorescence quantum yields of 1, A. Saeki (Osaka University) for measuring the time-dependent emission profile of 1, and K. Yamamoto and K. Albrecht (Tokyo Institute of Technology) for their support with measuring the fluorescence lifetimes of boron compounds. Some of the present calculations were performed at the Research Center for Computational Science (RCCS) Okazaki Research Facilities, and National Institutes of Natural Sciences (NINS).
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/2/22
Y1 - 2017/2/22
N2 - 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-Cipso moiety in the T1 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.
AB - 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-Cipso moiety in the T1 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.
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U2 - 10.1021/jacs.6b11984
DO - 10.1021/jacs.6b11984
M3 - Article
C2 - 28135418
AN - SCOPUS:85013419019
SN - 0002-7863
VL - 139
SP - 2728
EP - 2733
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 7
ER -