Hidden Isolated OH at the Charged Hydrophobic Interface Revealed by Two-Dimensional Heterodyne-Detected VSFG Spectroscopy

Mohammed Ahmed, Ken ichi Inoue, Satoshi Nihonyanagi, Tahei Tahara

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Water around hydrophobic groups mediates hydrophobic interactions that play key roles in many chemical and biological processes. Thus, the molecular-level elucidation of the properties of water in the vicinity of hydrophobic groups is important. We report on the structure and dynamics of water at two oppositely charged hydrophobic ion/water interfaces, that is, the tetraphenylborate-ion (TPB)/water and tetraphenylarsonium-ion (TPA+)/water interfaces, which are clarified by two-dimensional heterodyne-detected vibrational sum-frequency generation (2D HD-VSFG) spectroscopy. The obtained 2D HD-VSFG spectra of the anionic TPB interface reveal the existence of distinct π-hydrogen bonded OH groups in addition to the usual hydrogen-bonded OH groups, which are hidden in the steady-state spectrum. In contrast, 2D HD-VSFG spectra of the cationic TPA+ interface only show the presence of usual hydrogen-bonded OH groups. The present study demonstrates that the sign of the interfacial charge governs the structure and dynamics of water molecules that face the hydrophobic region.

Original languageEnglish
Pages (from-to)9498-9505
Number of pages8
JournalAngewandte Chemie - International Edition
Volume59
Issue number24
DOIs
Publication statusPublished - 2020 Jun 8

Keywords

  • hydrophobic interfaces
  • interfacial water
  • sum-frequency generation
  • ultrafast spectroscopy
  • vibrational dynamics

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

Fingerprint Dive into the research topics of 'Hidden Isolated OH at the Charged Hydrophobic Interface Revealed by Two-Dimensional Heterodyne-Detected VSFG Spectroscopy'. Together they form a unique fingerprint.

Cite this