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Room‐Temperature Phosphorescence of Crystalline 1,4‐Bis(aroyl)‐2,5‐dibromobenzenes
Author(s) -
Shimizu Masaki,
Kimura Akinori,
Sakaguchi Hiroshi
Publication year - 2016
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201501382
Subject(s) - phosphorescence , chemistry , luminescence , photoluminescence , intramolecular force , photochemistry , intermolecular force , excited state , benzene , crystal (programming language) , molecule , stereochemistry , organic chemistry , fluorescence , materials science , optoelectronics , physics , computer science , nuclear physics , programming language , quantum mechanics
There is a growing interest in metal‐free organic luminophores that exhibit phosphorescence at room temperature. We report herein that 1,4‐bis(aroyl)‐2,5‐dibromobenzenes serve as a new class of such luminophores. The bis(aroyl)benzene derivatives were not emissive either in solution or in a doped polymer thin film. In contrast, crystals of bis(aroyl)benzenes showed photoluminescence under ambient conditions, which was subsequently confirmed as phosphorescence with a luminescence lifetime measurement. The emission color ranged from blue to green, depending on the nature of the aroyl groups, and the luminescent quantum yields were 0.05–0.18 at room temperature and 0.38–0.67 at 77 K. In each crystal, several intermolecular interactions such as C=O ··· H, Br ··· Br, C=O ··· Br, F ··· F, S ··· H, and MeO ··· H were observed, which contributed to the restriction of intramolecular motions, thereby diminishing the nonradiative decay process from the triplet excited states.