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Zhang S, Yan Y, Zhou Q, Fan Y. Ionic Liquid-Based Extraction Strategy for the Efficient and Selective Recovery of Scandium. Molecules 2024; 29:4007. [PMID: 39274855 PMCID: PMC11396334 DOI: 10.3390/molecules29174007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2024] [Revised: 08/05/2024] [Accepted: 08/22/2024] [Indexed: 09/16/2024] Open
Abstract
The recovery of scandium (Sc) from highly acidic industrial effluents is currently hindered by the use of large quantities of flammable and toxic organic solvents. This study developed an extraction system using ionic liquids (ILs) and phenylphosphinic acid (PPAH) as diluents and an extractant, respectively, to selectively recover Sc from the aqueous phase. The effect of IL chemical structure, aqueous pH and temperature on the extraction of Sc was systematically investigated and the findings revealed that ILs with longer alkyl side chains had reduced Sc extraction ability due to the presence of continuous nonpolar domains formed by the self-aggregation of the IL alkyl side chain. The IL/PPAH system maintained high extraction ability toward Sc across a wide temperature range (288 K to 318 K) and the extraction efficiency of Sc could be improved significantly by increasing the aqueous pH. The extraction process involved proton exchange, resulting in the formation of a metal-ligand complex (Sc(PPA)3).
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Affiliation(s)
- Sheli Zhang
- School of Science and Technology, Jiaozuo Teachers College, Jiaozuo 454000, China
| | - Yuerong Yan
- School of Science and Technology, Jiaozuo Teachers College, Jiaozuo 454000, China
| | - Qiang Zhou
- College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454003, China
| | - Yunchang Fan
- College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454003, China
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2
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Pontoni D, DiMichiel M, Murphy BM, Honkimäki V, Deutsch M. Ordering of ionic liquids at a charged sapphire interface: Evolution with cationic chain length. J Colloid Interface Sci 2024; 661:33-45. [PMID: 38295701 DOI: 10.1016/j.jcis.2024.01.126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/09/2024] [Accepted: 01/18/2024] [Indexed: 02/27/2024]
Abstract
HYPOTHESIS Room Temperature Ionic Liquids (RTILs) bulk's molecular layering dominates their structure also at the RTIL/sapphire interface, increasing the layer spacing with the cationic alkyl chain length n. However, the negatively-charged sapphire surface compresses the layers, increases the layering range, and affects the intra-layer structure in yet unknown ways. EXPERIMENTS X-ray reflectivity (XR) off the RTIL/sapphire interface, for a broad homologous RTIL series 1-alkyl-3-methylimidazolium bis(trifluoromethansulfonyl)imide, hitherto unavailable for any RTIL. FINDINGS RTIL layers against the sapphire, exhibit two spacings: da and db. da is n-varying, follows the behavior of the bulk spacing but exhibits a downshift, thus showing significant layer compression, and over twofold polar slab thinning. The latter suggests exclusion of anions from the interfacial region due to the negative sapphire charging by x-ray-released electrons. The layering range is larger than the bulk's. db is short and near n-independent, suggesting polar moieties' layering, the coexistence mode of which with the da-spaced layering is unclear. Comparing the present layering with the bulk's and the RTIL/air interface's provides insight into the Coulomb and dispersion interaction balance dominating the RTIL's structure and the impact thereon of the presence of a charged solid interface.
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Affiliation(s)
- Diego Pontoni
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Marco DiMichiel
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Bridget M Murphy
- Institute of Experimental and Applied Physics, Kiel University, Kiel D-24098, Germany; Ruprecht-Haensel Laboratory, Kiel University, Kiel D-24118, Germany
| | - Veijo Honkimäki
- ESRF - The European Synchrotron, 71 Avenue des Martyrs, 38043 Grenoble, France
| | - Moshe Deutsch
- Physics Dept. & Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel.
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3
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McGrogan A, Lafferty J, O’Neill L, Brown L, Young JM, Goodrich P, Muldoon MJ, Moura L, Youngs S, Hughes TL, Gärtner S, Youngs TGA, Holbrey JD, Swadźba-Kwaśny M. Liquid Structure of Ionic Liquids with [NTf 2] - Anions, Derived from Neutron Scattering. J Phys Chem B 2024; 128:3220-3235. [PMID: 38520396 PMCID: PMC11000221 DOI: 10.1021/acs.jpcb.3c08069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 02/28/2024] [Accepted: 03/12/2024] [Indexed: 03/25/2024]
Abstract
The liquid structure of three common ionic liquids (ILs) was investigated by neutron scattering for the first time. The ILs were based on the bis(trifluoromethanesulfonyl)imide anion, abbreviated in the literature as [NTf2]- or [TFSI]-, and on the following cations: 1-ethyl-3-methylimidazolium, [C2mim]+; 1-decyl-3-methylimidazolium, [C10mim]+; and trihexyl(tetradecyl)phosphonium, [P666,14]+. Comparative analysis of the three ILs confirmed increased size of nonpolar nanodomains with increasing bulk of alkyl chains. It also sheds light on the cation-anion interactions, providing experimental insight into strength, directionality, and angle of hydrogen bonds between protons on the imidazolium ring, as well as H-C-P protons in [P666,14]+, to oxygen and nitrogen atoms in the [NTf2]-. The new Dissolve data analysis package enabled, for the first time, the analysis of neutron scattering data of ILs with long alkyl chains, in particular, of [P666,14][NTf2]. Results generated with Dissolve were validated by comparing outputs from three different models, starting from three different sets of cation charges, for each of the three ILs, which gave convergent outcomes. Finally, a modified method for the synthesis of perdeuterated [P666,14][NTf2] has been reported, with the aim of reporting a complete set of synthetic and data processing approaches, laying robust foundations that enable the study of the phosphonium ILs family by neutron scattering.
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Affiliation(s)
- Anne McGrogan
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
| | - Jack Lafferty
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
| | - Lauren O’Neill
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
| | - Lucy Brown
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
| | - J. Mark. Young
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
| | - Peter Goodrich
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
| | - Mark J. Muldoon
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
| | - Leila Moura
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
| | - Sarah Youngs
- Rutherford
Appleton Laboratory, Chilton, Didcot OX11 0QX, U.K.
| | | | - Sabrina Gärtner
- Rutherford
Appleton Laboratory, Chilton, Didcot OX11 0QX, U.K.
| | | | - John D. Holbrey
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
| | - Małgorzata Swadźba-Kwaśny
- QUILL
Research Centre, Queen’s University Belfast, School of Chemistry and Chemical Engineering, David Keir Building, 39-123 Stranmillis Road, Belfast BT9 5AG, Belfast, U.K.
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4
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Kim SJ, Jeong JS, Jang HW, Yi H, Yang H, Ju H, Lim JA. Dendritic Network Implementable Organic Neurofiber Transistors with Enhanced Memory Cyclic Endurance for Spatiotemporal Iterative Learning. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2100475. [PMID: 34028897 DOI: 10.1002/adma.202100475] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Indexed: 06/12/2023]
Abstract
Dendritic network implementable organic neurofiber transistors with enhanced memory cyclic endurance for spatiotemporal iterative learning are proposed. The architecture of the fibrous organic electrochemical transistors consisting of a double-stranded assembly of electrode microfibers and an iongel gate insulator enables the highly sensitive multiple implementation of synaptic junctions via simple physical contact of gate-electrode microfibers, similar to the dendritic connections of a biological neuron fiber. In particular, carboxylic-acid-functionalized polythiophene as a semiconductor channel material provides stable gate-field-dependent multilevel memory characteristics with long-term stability and cyclic endurance, unlike the conventional poly(alkylthiophene)-based neuromorphic electrochemical transistors, which exhibit short retention and unstable endurance. The dissociation of the carboxylic acid of the polythiophene enables reversible doping and dedoping of the polythiophene channel by effectively stabilizing the ions that penetrate the channel during potentiation and depression cycles, leading to the reliable cyclic endurance of the device. The synaptic weight of the neurofiber transistors with a dendritic network maintains the state levels stably and is independently updated with each synapse connected with the presynaptic neuron to a specific state level. Finally, the neurofiber transistor demonstrates successful speech recognition based on iterative spiking neural network learning in the time domain, showing a substantial recognition accuracy of 88.9%.
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Affiliation(s)
- Soo Jin Kim
- Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jae-Seung Jeong
- Center for Neuromorphic Engineering, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
- Division of Nano and Information Technology, University of Science and Technology of Korea, Daejeon, 34113, Republic of Korea
| | - Ho Won Jang
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
- Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Hyunjung Yi
- Post-Silicon Semiconductor Institute, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
- Department of Materials Science and Engineering, YU-KIST Institute, Yonsei University, Seoul, 03722, Republic of Korea
| | - Hoichang Yang
- Department of Chemical Engineering, Inha University, Incheon, 22212, Republic of Korea
| | - Hyunsu Ju
- Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
| | - Jung Ah Lim
- Center for Opto-Electronic Materials and Devices, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
- Division of Nano and Information Technology, University of Science and Technology of Korea, Daejeon, 34113, Republic of Korea
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5
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Cimini A, Palumbo O, Trequattrini F, Paolone A. Influence of the Alkyl Chain Length on the Low Temperature Phase Transitions of Imidazolium Based Ionic Liquids. J SOLUTION CHEM 2021. [DOI: 10.1007/s10953-021-01079-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Philippi F, Welton T. Targeted modifications in ionic liquids - from understanding to design. Phys Chem Chem Phys 2021; 23:6993-7021. [PMID: 33876073 DOI: 10.1039/d1cp00216c] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ionic liquids are extremely versatile and continue to find new applications in academia as well as industry. This versatility is rooted in the manifold of possible ion types, ion combinations, and ion variations. However, to fully exploit this versatility, it is imperative to understand how the properties of ionic liquids arise from their constituents. In this work, we discuss targeted modifications as a powerful tool to provide understanding and to enable design. A 'targeted modification' is a deliberate change in the structure of an ionic liquid. This includes chemical changes in an experiment as well as changes to the parameterisation in a computer simulation. In any case, such a change must be purposeful to isolate what is of interest, studying, as far as is possible, only one concept at a time. The concepts can then be used as design elements. However, it is often found that several design elements interact with each other - sometimes synergistically, and other times antagonistically. Targeted modifications are a systematic way of navigating these overlaps. We hope this paper shows that understanding ionic liquids requires experimentalists and theoreticians to join forces and provides a tool to tackle the difficult transition from understanding to design.
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Affiliation(s)
- Frederik Philippi
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, London W12 0BZ, UK.
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7
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Pontoni D, DiMichiel M, Deutsch M. Nanoscale Structure in Short‐Chain Ionic Liquids. Chemphyschem 2020; 21:1887-1897. [DOI: 10.1002/cphc.202000548] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Indexed: 02/03/2023]
Affiliation(s)
- Diego Pontoni
- Partnership for Soft Condensed Matter (PSCM) ESRF – The European Synchrotron 71 Avenue des Martyrs 38043 Grenoble France
| | - Marco DiMichiel
- ESRF – The European Synchrotron 71 Avenue des Martyrs 38043 Grenoble France
| | - Moshe Deutsch
- Physics Dept. & Institute of Nanotechnology and Advanced Materials Bar-Ilan University Ramat Gan Israel
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8
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Pontoni D, DiMichiel M, Deutsch M. Temperature evolution of the bulk nano-structure in a homologous series of room temperature ionic liquids. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.112280] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Deb D, Bhattacharya S. Ion transport in surface functionalized SnO2 nanoparticles dispersed imidazolium ionanofluids: Decoupling from structural relaxation. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.04.101] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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10
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Haddad B, Paolone A, Drai M, Boumediene M, Villemin D, Belarbi EH, Rahmouni M, Bresson S, Abbas O. Para-xylyl linked bis-imidazolium ionic liquids: A study of the conformers of the cation and of the anion-cation hydrogen bonding. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.07.096] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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11
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Haddad J, Pontoni D, Murphy BM, Festersen S, Runge B, Magnussen OM, Steinrück HG, Reichert H, Ocko BM, Deutsch M. Surface structure evolution in a homologous series of ionic liquids. Proc Natl Acad Sci U S A 2018; 115:E1100-E1107. [PMID: 29358372 PMCID: PMC5819424 DOI: 10.1073/pnas.1716418115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interfaces of room temperature ionic liquids (RTILs) are important for both applications and basic science and are therefore intensely studied. However, the evolution of their interface structure with the cation's alkyl chain length [Formula: see text] from Coulomb to van der Waals interaction domination has not yet been studied for even a single broad homologous RTIL series. We present here such a study of the liquid-air interface for [Formula: see text], using angstrom-resolution X-ray methods. For [Formula: see text], a typical "simple liquid" monotonic surface-normal electron density profile [Formula: see text] is obtained, like those of water and organic solvents. For [Formula: see text], increasingly more pronounced nanoscale self-segregation of the molecules' charged moieties and apolar chains yields surface layering with alternating regions of headgroups and chains. The layering decays into the bulk over a few, to a few tens, of nanometers. The layering periods and decay lengths, their linear [Formula: see text] dependence, and slopes are discussed within two models, one with partial-chain interdigitation and the other with liquid-like chains. No surface-parallel long-range order is found within the surface layer. For [Formula: see text], a different surface phase is observed above melting. Our results also impact general liquid-phase issues like supramolecular self-aggregation and bulk-surface structure relations.
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Affiliation(s)
- Julia Haddad
- Physics Department, Bar-Ilan University, Ramat Gan 5290002, Israel
- Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Diego Pontoni
- European Synchrotron Radiation Facility, The European Synchrotron and Partnership for Soft Condensed Matter (PSCM), 38000 Grenoble, France
| | - Bridget M Murphy
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
- Ruprecht Haensel Laboratory, Kiel University, 24098 Kiel, Germany
| | - Sven Festersen
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
| | - Benjamin Runge
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
| | - Olaf M Magnussen
- Institute for Experimental and Applied Physics, Kiel University, 24118 Kiel, Germany
- Ruprecht Haensel Laboratory, Kiel University, 24098 Kiel, Germany
| | - Hans-Georg Steinrück
- Stanford Synchrotron Radiation Laboratory (SSRL) Materials Science Division, Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory, Menlo Park, CA 94025
| | - Harald Reichert
- European Synchrotron Radiation Facility, The European Synchrotron, 38000 Grenoble, France
| | - Benjamin M Ocko
- National Synchrotron Light Source II (NSLS-II), Brookhaven National Laboratory, Upton, NY 11973
| | - Moshe Deutsch
- Physics Department, Bar-Ilan University, Ramat Gan 5290002, Israel;
- Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan 5290002, Israel
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12
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Yoshimura Y, Takekiyo T, Koyama Y, Takaku M, Yamamura M, Kikuchi N, Wakabayashi D, Funamori N, Matsuishi K, Abe H, Hamaya N. High-pressure glass formation of a series of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide homologues. Phys Chem Chem Phys 2018; 20:199-205. [DOI: 10.1039/c7cp06594a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
[Cnmim][TFSI] resists external pressure and retains the local liquid structure, as if a sponge absorbs a stimulus.
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Affiliation(s)
| | - Takahiro Takekiyo
- Department of Applied Chemistry
- National Defense Academy
- Yokosuka
- Japan
| | - Yoshihiro Koyama
- Graduate School of Pure and Applied Science
- University of Tsukuba
- Ibaraki 305-8537
- Japan
| | - Mayumi Takaku
- Graduate School of Humanities and Sciences
- Ochanomizu University
- Tokyo 112-8610
- Japan
| | - Misaho Yamamura
- Graduate School of Humanities and Sciences
- Ochanomizu University
- Tokyo 112-8610
- Japan
| | - Natsumi Kikuchi
- Graduate School of Humanities and Sciences
- Ochanomizu University
- Tokyo 112-8610
- Japan
| | - Daisuke Wakabayashi
- Institute of Materials Structure Science
- High Energy Accelerator Research Organization (KEK)
- Tsukuba 305-0801
- Japan
| | - Nobumasa Funamori
- Institute of Materials Structure Science
- High Energy Accelerator Research Organization (KEK)
- Tsukuba 305-0801
- Japan
| | - Kiyoto Matsuishi
- Graduate School of Pure and Applied Science
- University of Tsukuba
- Ibaraki 305-8537
- Japan
| | - Hiroshi Abe
- Department of Materials Science and Engineering
- National Defense Academy
- Yokosuka
- Japan
| | - Nozomu Hamaya
- Graduate School of Humanities and Sciences
- Ochanomizu University
- Tokyo 112-8610
- Japan
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13
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Effect of anion and alkyl chain length on the structure and interactions of N -alkyl pyridinium ionic liquids. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.05.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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14
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Reid JESJ, Gammons RJ, Slattery JM, Walker AJ, Shimizu S. Interactions in Water–Ionic Liquid Mixtures: Comparing Protic and Aprotic Systems. J Phys Chem B 2017; 121:599-609. [DOI: 10.1021/acs.jpcb.6b10562] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Joshua E. S. J. Reid
- York
Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
- TWI Ltd., Granta Park, Great Abington, Cambridge, CB21 6AL, U.K
| | - Richard J. Gammons
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - John M. Slattery
- Department
of Chemistry, University of York, Heslington, York YO10
5DD, U.K
| | - Adam J. Walker
- TWI Ltd., Granta Park, Great Abington, Cambridge, CB21 6AL, U.K
| | - Seishi Shimizu
- York
Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5DD, U.K
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Abstract
Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.
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Affiliation(s)
- Vitor H Paschoal
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo , Av. Prof. Lineu Prestes 748, São Paulo 05508-000, Brazil
| | - Luiz F O Faria
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo , Av. Prof. Lineu Prestes 748, São Paulo 05508-000, Brazil
| | - Mauro C C Ribeiro
- Laboratório de Espectroscopia Molecular, Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo , Av. Prof. Lineu Prestes 748, São Paulo 05508-000, Brazil
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