π–π Interactions: Influence on Molecular Packing and Solid-State Emission of ESIPT and non-ESIPT Motifs

Vikas S. Padalkar, Daisuke Sakamaki, Kenji Kuwada, Akifumi Horio, Haruka Okamoto, Norimitsu Tohnai, Tomoyuki Akutagawa, Ken Ichi Sakai, Shu Seki

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Novel, triphenylamino benzothiazole-based excited-state intramolecular proton transfer (ESIPT) and non-ESIPT fluorophores were prepared by Suzuki coupling reactions. Their photophysical properties in solution, aqueous suspension, and in the solid state were systematically investigated. High fluorescence quantum efficiencies (Φsol≈95 %; Φsolid≈88 %), moderate Stokes shifts (≈8000 cm−1), microenvironment-sensitive and molecular-framework-dependent emission are the striking features of the protocol described here. Solid-state emission was modulated and interpreted as a crossover effect of π–π interactions using single-crystal X-ray analyses. The nonplanar/twisted framework of the system helps to avoid noncovalent interactions, facilitating the suppression of fluorescence quenching in the solid state with high quantum efficiency over 88 %.

Original languageEnglish
Pages (from-to)938-945
Number of pages8
JournalAsian Journal of Organic Chemistry
Volume5
Issue number7
DOIs
Publication statusPublished - 2016 Jul 1

Keywords

  • aggregation-induced emission
  • excited-state intramolecular proton transfer
  • fluorescence
  • molecular packing
  • photophysics

ASJC Scopus subject areas

  • Organic Chemistry

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    Padalkar, V. S., Sakamaki, D., Kuwada, K., Horio, A., Okamoto, H., Tohnai, N., Akutagawa, T., Sakai, K. I., & Seki, S. (2016). π–π Interactions: Influence on Molecular Packing and Solid-State Emission of ESIPT and non-ESIPT Motifs. Asian Journal of Organic Chemistry, 5(7), 938-945. https://doi.org/10.1002/ajoc.201600159