Sulfur-Based Intramolecular Hydrogen-Bond: Excited-State Hydrogen-Bond On/Off Switch with Dual Room-Temperature Phosphorescence

Zong Ying Liu, Jiun Wei Hu, Chun Hao Huang, Teng Hsing Huang, Deng Gao Chen, Ssu Yu Ho, Kew Yu Chen, Elise Y. Li, Pi Tai Chou

Research output: Contribution to journalArticle

8 Citations (Scopus)


We report O-H-S hydrogen-bond (H-bond) formation and its excited-state intramolecular H-bond on/off reaction unveiled by room-temperature phosphorescence (RTP). In this seminal work, this phenomenon is demonstrated with 7-hydroxy-2,2-dimethyl-2,3-dihydro-1H-indene-1-thione (DM-7HIT), which possesses a strong polar (hydroxy)-dispersive (thione) type H-bond. Upon excitation, DM-7HIT exhibits anomalous dual RTP with maxima at 550 and 685 nm. This study found that the lowest lying excited state (S1) of DM-7HIT is a sulfur nonbonding (n) to π∗ transition, which undergoes O-H bond flipping from S1(nπ*) to the non-H-bonded S′1(nπ*) state, followed by intersystem crossing and internal conversion to populate the T′1(nπ*) state. Fast H-bond on/off switching then takes place between T′1(nπ*) and T1(nπ*), forming a pre-equilibrium that affords both the T′1(nπ*, 685 nm) and T1(nπ*, 550 nm) RTP. The generality of the sulfur H-bond on/off switching mechanism, dubbed a molecule wiper, was rigorously evaluated with a variety of other H-bonded thiones, and these results open a new chapter in the chemistry of hydrogen bonds.

Original languageEnglish
Pages (from-to)9885-9894
Number of pages10
JournalJournal of the American Chemical Society
Issue number25
Publication statusPublished - 2019 Jun 26


ASJC Scopus subject areas

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

Cite this