Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 13, 2020
Previous Article Next Article

Counting cations involved in cationic clusters of hydroxy-functionalized ionic liquids by means of infrared and solid-state NMR spectroscopy

Author affiliations

Abstract

In hydroxy-functionalized ionic liquids, two types of hydrogen bonding coexist: the conventional H-bonds between cation and anion (c–a) and those between cation and cation (c–c), although the interaction between like-charged ions is supposed to be much weaker due to the repulsive Coulomb forces. Counting the cations involved in either (c–a) or (c–c) clusters is a challenge. For that purpose, we recently performed neutron diffraction (ND) measurements and molecular dynamics (MD) simulations at and above room temperature accompanied by NMR solid-state experiments in the glassy state of the ILs. In principle, these methods are suitable for determining the populations of (c–a) and (c–c) cluster species. For different reasons we could only address single temperatures and/or small temperature intervals above 300 K. The by far largest temperature range with reasonable efforts is accessible by simple infrared (IR) spectroscopy. However, counting (c–a) or (c–c) hydrogen bonds is a difficult task due to the different transition dipole moments resulting in varying intensities and broad vibrational bands. Here we present a method for deriving the number of cations involved in (c–a) ion pairs from IR spectra in the OH stretch region. This procedure provides access to the equilibria of (c–a) and (c–c) hydrogen bonds as a function of temperature allowing derivation of the transition enthalpy.

Graphical abstract: Counting cations involved in cationic clusters of hydroxy-functionalized ionic liquids by means of infrared and solid-state NMR spectroscopy

Back to tab navigation

Supplementary files

Article information


Submitted
17 Jan 2020
Accepted
15 Mar 2020
First published
16 Mar 2020

Phys. Chem. Chem. Phys., 2020,22, 6861-6867
Article type
Paper

Counting cations involved in cationic clusters of hydroxy-functionalized ionic liquids by means of infrared and solid-state NMR spectroscopy

A. Strate, J. Neumann, T. Niemann, P. Stange, A. E. Khudozhitkov, A. G. Stepanov, D. Paschek, D. I. Kolokolov and R. Ludwig, Phys. Chem. Chem. Phys., 2020, 22, 6861
DOI: 10.1039/D0CP00303D

Social activity

Search articles by author

Spotlight

Advertisements