Room-Temperature Phosphorescence of Crystalline Metal-Free Organoboron Complex.
The photoluminescence (PL) properties of a metal-free organoboron complex, bis(4-iodobenzoyl)methanatoboron difluoride (1BF2), were elucidated. At room temperature, 1BF2emits blue fluorescence (FL) in nBuCl upon photoexcitation. In contrast, crystals of 1BF2emit green PL comprised of FL and phosphorescence (PH). The room-temperature PH of crystalline 1BF2is a consequence of 1) suppression of thermal deactivation of the S1and T1excited states and 2) enhancement of intersystem crossing (ISC) from the S1to T2or T1. The results of X-ray crystallographic and theoretical studies supported the proposal that the former (1) is a result of intermolecular interactions caused by π-stacking in the rigid crystal packing structure of 1BF2. The latter (2) is an effect of not only the heavy-atom effect of iodine, but also the continuous π-stacking alignment of 1BF2molecules in crystals, which leads to a forbidden S1→S0transition and a small energy gap between the S1and T2or T1.
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.
Atsushi
A
Sakai
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.|The Research Institute for Molecular Electronic Devices, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.
Eisuke
E
Ohta
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.|The Research Institute for Molecular Electronic Devices, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.
Yasunori
http://orcid.org/0000-0002-7719-0071
Y
Matsui
Research Center for Computational Design of Advanced Functional Materials (CD-FMat), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8568, Japan.
Seiji
S
Tsuzuki
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.|The Research Institute for Molecular Electronic Devices, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan.
Hiroshi
H
Ikeda
density functional calculations; intermolecular interactions; iodine; metal-free materials; photochemistry