Imidazole-based excited-state intramolecular proton-transfer materials: Synthesis and amplified spontaneous emission from a large single crystal

Sanghyuk Park, Oh Hoon Kwon, Sehoon Kim, Sangwoo Park, Moon Gun Choi, Myoungsik Cha, Soo Young Park, Du Jeon Jang

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We have synthesized a novel class of imidazole-based excited-state intramolecular proton-transfer (ESIPT) materials, i.e., hydroxy-substituted tetraphenylimidazole (HPI) and its derivative HPI-Ac, which formed large single crystals exhibiting intense blue fluorescence and amplified spontaneous emission (ASE). Transparent, clear, and well-defined fluorescent single crystals of HPI-Ac as large as 20 mm × 25 mm × 5 mm were easily grown from its dilute solution. From the X-ray crystallographic analysis and semiempirical molecular orbital calculation, it was deduced that the four phenyl groups substituted into the imidazole ring of HPI and HPI-Ac allowed the crystals free from concentration quenching of fluorescence by limiting the excessive tight-stacking responsible for intermolecular vibrational coupling and relevant nonradiative relaxation. Fluorescence spectral narrowing and efficient ASE were observed in the HPI-Ac single crystal even at low excitation levels attributed to the intrinsic four-level ESIPT photocycle.

Original languageEnglish
Pages (from-to)10070-10074
Number of pages5
JournalJournal of the American Chemical Society
Issue number28
Publication statusPublished - 2005 Jul 20


All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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