Issue 13, 2015

Hydrogen bonding in a mixture of protic ionic liquids: a molecular dynamics simulation study

Abstract

We report results of molecular dynamics (MD) simulations characterising the hydrogen bonding in mixtures of two different protic ionic liquids sharing the same cation: triethylammonium-methylsulfonate (TEAMS) and triethylammonium-triflate (TEATF). The triethylammonium-cation acts as a hydrogen-bond donor, being able to donate a single hydrogen-bond. Both, the methylsulfonate- and the triflate-anions can act as hydrogen-bond acceptors, which can accept multiple hydrogen bonds via their respective SO3-groups. In addition, replacing a methyl-group in the methylsulfonate by a trifluoromethyl-group in the triflate significantly weakens the strength of a hydrogen bond from an adjacent triethylammonium cation to the oxygen-site in the SO3-group of the anion. Our MD simulations show that these subtle differences in hydrogen bond strength significantly affect the formation of differently-sized hydrogen-bonded aggregates in these mixtures as a function of the mixture-composition. Moreover, the reported hydrogen-bonded cluster sizes can be predicted and explained by a simple combinatorial lattice model, based on the approximate coordination number of the ions, and using statistical weights that mostly account for the fact that each anion can only accept three hydrogen bonds.

Graphical abstract: Hydrogen bonding in a mixture of protic ionic liquids: a molecular dynamics simulation study

Article information

Article type
Paper
Submitted
21 Nov 2014
Accepted
20 Jan 2015
First published
21 Jan 2015
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2015,17, 8431-8440

Author version available

Hydrogen bonding in a mixture of protic ionic liquids: a molecular dynamics simulation study

D. Paschek, B. Golub and R. Ludwig, Phys. Chem. Chem. Phys., 2015, 17, 8431 DOI: 10.1039/C4CP05432F

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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