Enhanced solid-state fluorescence in the oxadiazole-based excited-state intramolecular proton-transfer (ESIPT) material: Synthesis, optical property, and crystal structure

Jangwon Seo, Sehoon Kim, Young Shin Lee, Oh Hoon Kwon, Kang Hyun Park, Soo Young Choi, Young Keun Chung, Du Jeon Jang, Soo Young Park

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

We report highly fluorescent oxadiazole-based excited-state intramolecular proton-transfer (ESIPT) material, 2,5-bis-[5-(4-tert-butyl-phenyl)-[1,3,4]oxadiazol-2-yl]-phenol (SOX) in solid state film (Φf = 0.47) as well as in solution (Φf = 0.40). From the single crystal X-ray crystallography, a molecular geometry of SOX was found to be nearly planar due to the strong intramolecular hydrogen-bond between the hydroxyl and oxadiazole groups to give rise to the virtually single keto fluorescence. In view of the molecular arrangement, a specific dimer interaction caused by a Coulomb attraction in the SOX crystal was most likely associated with a sliding-away stacking, which contributed to the intense solid-state fluorescence. On the other hand, 2,5-bis-[5-(4-tert-butyl-phenyl)-[1,3,4]oxadiazol-2-yl]-benzene-1,4-diol (DOX) with dual ESIPT sites but otherwise the same as SOX showed a significantly red-shifted orange emission (λem = 573 nm) of keto tautomer relative to the bluish-green emission (λem = 486 nm) of SOX in chloroform. Similarly, the fluorescence emission of DOX in solid-state film (Φf = 0.13) was highly enhanced from that in solution (Φf = 0.02). Interestingly, SOX and DOX showed well-defined room-temperature phosphorescence. Kinetic studies on the ESIPT keto fluorescence as well as the phosphorescence were investigated using picosecond laser experiments.

Original languageEnglish
Pages (from-to)51-58
Number of pages8
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume191
Issue number1
DOIs
Publication statusPublished - 2007 Sep 7

Keywords

  • Enhanced solid-state fluorescence
  • Excited-state intramolecular proton-transfer (ESIPT)
  • Oxadiazole
  • Room-temperature phosphorescence

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

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