Spectroscopic Evidence for an Attractive Cation–Cation Interaction in Hydroxy‐Functionalized Ionic Liquids: A Hydrogen‐Bonded Chain‐like Trimer
Abstract
We address the formation of hydrogen bonded domains among the cationic constituents of the ionic liquid (IL) 1‐(3‐hydroxypropyl)pyridinium tetrafluoroborate [HPPy][BF4] by means of cryogenic ion vibrational predissociation spectroscopy of cold (ca. 35 K) gas‐phase cluster ions and quantum chemistry. Specifically, analysis of the OH stretching bands reveals a chain‐like OH⋅⋅⋅OH⋅⋅⋅OH⋅⋅⋅BF4− binding motif involving the three cations in the cationic quinary cluster ion (HPPy+)3(BF4−)2. Calculations show that this cooperative H‐bond attraction compensates for the repulsive Coulomb forces and results in stable complexes that successfully compete with those in which the OH groups are predominantly attached to the counter anions. Our combined experimental and theoretical approach provides insight into the cooperative effects that lead to the formation of hydrogen bonded domains involving the cationic constituents of ILs.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 24, 2018
- Source ID
- 10.1002/anie.201808381
Entities
People
- Anne Strate
- Fabian S Menges
- Helen J Zeng
- Mark A. Johnson
- Ralf Ludwig
- Thomas Niemann
Organizations
- Air Force Office of Scientific Research
- German Research Foundation
- University of Rostock
- Yale University