Premium
Room‐Temperature Phosphorescence of Crystalline Metal‐Free Organoboron Complex
Author(s) -
Sakai Atsushi,
Ohta Eisuke,
Matsui Yasunori,
Tsuzuki Seiji,
Ikeda Hiroshi
Publication year - 2016
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201600779
Subject(s) - phosphorescence , organoboron compounds , photochemistry , metal , chemistry , materials science , organic chemistry , fluorescence , catalysis , physics , optics
The photoluminescence (PL) properties of a metal‐free organoboron complex, bis(4‐iodobenzoyl)methanatoboron difluoride ( 1BF 2 ), were elucidated. At room temperature, 1BF 2 emits blue fluorescence (FL) in n BuCl upon photoexcitation. In contrast, crystals of 1BF 2 emit green PL comprised of FL and phosphorescence (PH). The room‐temperature PH of crystalline 1BF 2 is a consequence of 1) suppression of thermal deactivation of the S 1 and T 1 excited states and 2) enhancement of intersystem crossing (ISC) from the S 1 to T 2 or T 1 . 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 1BF 2 . The latter (2) is an effect of not only the heavy‐atom effect of iodine, but also the continuous π‐stacking alignment of 1BF 2 molecules in crystals, which leads to a forbidden S 1 →S 0 transition and a small energy gap between the S 1 and T 2 or T 1 .