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Title: Structure of cyano-anion ionic liquids: X-ray scattering and simulations

Abstract

Ionic liquids with cyano anions have long been used because of their unique combination of low-melting temperatures, reduced viscosities, and increased conductivities. Recently we have shown that cyano anions in ionic liquids are particularly interesting for their potential use as electron donors to excited state photo-acceptors [B. Wu et al., J. Phys. Chem. B 119, 14790–14799 (2015)]. Here we report on bulk structural and quantum mechanical results for a series of ionic liquids based on the 1-ethyl-3-methylimidazolium cation, paired with the following five cyano anions: SeCN-, SCN-, N(CN)-2N(CN)2-, C(CN)-3C(CN)3-, and B(CN)-4B(CN)4-. By combining molecular dynamics simulations, high-energy X-ray scattering measurements, and periodic boundary condition DFT calculations, we are able to obtain a comprehensive description of the liquid landscape as well as the nature of the HOMO-LUMO states for these ionic liquids in the condensed phase. Features in the structure functions for these ionic liquids are somewhat different than the commonly observed adjacency, charge-charge, and polarity peaks, especially for the bulkiest B(CN)-4B(CN)4- anion. While the other four cyano-anion ionic liquids present an anionic HOMO, the one for Im+2,1Im2,1+/B(CN)-4B(CN)4- is cationic.

Authors:
; ORCiD logo; ORCiD logo; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
FOREIGN
OSTI Identifier:
1351355
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 145; Journal Issue: 2
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Dhungana, Kamal B., Faria, Luiz F. O., Wu, Boning, Liang, Min, Ribeiro, Mauro C. C., Margulis, Claudio J., and Castner, Edward W. Structure of cyano-anion ionic liquids: X-ray scattering and simulations. United States: N. p., 2016. Web. doi:10.1063/1.4955186.
Dhungana, Kamal B., Faria, Luiz F. O., Wu, Boning, Liang, Min, Ribeiro, Mauro C. C., Margulis, Claudio J., & Castner, Edward W. Structure of cyano-anion ionic liquids: X-ray scattering and simulations. United States. doi:10.1063/1.4955186.
Dhungana, Kamal B., Faria, Luiz F. O., Wu, Boning, Liang, Min, Ribeiro, Mauro C. C., Margulis, Claudio J., and Castner, Edward W. Thu . "Structure of cyano-anion ionic liquids: X-ray scattering and simulations". United States. doi:10.1063/1.4955186.
@article{osti_1351355,
title = {Structure of cyano-anion ionic liquids: X-ray scattering and simulations},
author = {Dhungana, Kamal B. and Faria, Luiz F. O. and Wu, Boning and Liang, Min and Ribeiro, Mauro C. C. and Margulis, Claudio J. and Castner, Edward W.},
abstractNote = {Ionic liquids with cyano anions have long been used because of their unique combination of low-melting temperatures, reduced viscosities, and increased conductivities. Recently we have shown that cyano anions in ionic liquids are particularly interesting for their potential use as electron donors to excited state photo-acceptors [B. Wu et al., J. Phys. Chem. B 119, 14790–14799 (2015)]. Here we report on bulk structural and quantum mechanical results for a series of ionic liquids based on the 1-ethyl-3-methylimidazolium cation, paired with the following five cyano anions: SeCN-, SCN-, N(CN)-2N(CN)2-, C(CN)-3C(CN)3-, and B(CN)-4B(CN)4-. By combining molecular dynamics simulations, high-energy X-ray scattering measurements, and periodic boundary condition DFT calculations, we are able to obtain a comprehensive description of the liquid landscape as well as the nature of the HOMO-LUMO states for these ionic liquids in the condensed phase. Features in the structure functions for these ionic liquids are somewhat different than the commonly observed adjacency, charge-charge, and polarity peaks, especially for the bulkiest B(CN)-4B(CN)4- anion. While the other four cyano-anion ionic liquids present an anionic HOMO, the one for Im+2,1Im2,1+/B(CN)-4B(CN)4- is cationic.},
doi = {10.1063/1.4955186},
journal = {Journal of Chemical Physics},
number = 2,
volume = 145,
place = {United States},
year = {Thu Jul 14 00:00:00 EDT 2016},
month = {Thu Jul 14 00:00:00 EDT 2016}
}