1
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Nachaki E, Kuroda DG. Lithium ion Speciation in Cyclic Solvents: Impact of Anion Charge Delocalization and Solvent Polarizability. J Phys Chem B 2024; 128:3408-3415. [PMID: 38546442 PMCID: PMC11017243 DOI: 10.1021/acs.jpcb.3c06872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 04/12/2024]
Abstract
The increasing demand for lithium batteries has triggered the search for safer and more efficient electrolytes. Insights into the atomistic description of electrolytes are critical for relating microscopic and macroscopic (physicochemical) properties. Previous studies have shown that the type of lithium salt and solvent used in the electrolyte influences its performance by dictating the speciation of the ionic components in the system. Here, we investigate the molecular origins of ion association in lithium-based electrolytes as a function of anion charge delocalization and solvent chemical identity. To this end, a family of cyano-based lithium salts in organic solvents, having a cyclic structure and containing carbonyl groups, was investigated using a combination of linear infrared spectroscopy and ab initio computations. Our results show that the formation of contact-ion pairs (CIPs) is more favorable in organic solvents containing either ester or carbonate groups and in lithium salts with an anion having low charge delocalization than in an amide/urea solvent and an anion with large charge delocalization. Ab initio computations attribute the degree of CIP formation to the energetics of the process, which is largely influenced by the chemical nature of the lithium ion solvation shell. At the molecular level, atomic charge analysis reveals that CIP formation is directly related to the ability of the solvent molecule to rearrange its electronic density upon coordination to the lithium ion. Overall, these findings emphasize the importance of local interactions in determining the nature of ion-molecule interactions and provide a molecular framework for explaining lithium ion speciation in the design of new electrolytes.
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Affiliation(s)
- Ernest
O. Nachaki
- Department of Chemistry, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
| | - Daniel G. Kuroda
- Department of Chemistry, Louisiana
State University, Baton
Rouge, Louisiana 70803, United States
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2
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Shin KS, Jang HG, Park SH, Cho SJ. Characteristics of ignition delay of hypergolic ionic liquids combined with 1-amino-4-methylpiperazine. RSC Adv 2023; 13:18960-18963. [PMID: 37362602 PMCID: PMC10285265 DOI: 10.1039/d3ra03752e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 06/15/2023] [Indexed: 06/28/2023] Open
Abstract
The ignition delay time of the hypergolic ionic liquids, 1-ethyl-3-methylimidazolium dicyanamide [EMIM][C2N3] and 1,3-dimethyl imidazolium dicyandiamide [DMIM][C2N3], can be controlled to approximately 20 ms by adding 1-amino-4-methylpiperazine while keeping the vapor pressure below 1 torr at 298 K.
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Affiliation(s)
- Kyung Su Shin
- Department of Chemical Engineering, Chonnam National University Gwangju 500-757 Korea
| | - Hoi-Gu Jang
- Department of Chemical Engineering, Chonnam National University Gwangju 500-757 Korea
| | - Soon Hee Park
- Department of Chemical Engineering, Chonnam National University Gwangju 500-757 Korea
| | - Sung June Cho
- Department of Chemical Engineering, Chonnam National University Gwangju 500-757 Korea
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3
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Tibbetts CA, Wyatt AB, Luther BM, Rappé AK, Krummel AT. Dicyanamide Anion Reports on Water Induced Local Structural and Dynamic Heterogeneity in Ionic Liquid Mixtures. J Phys Chem B 2023; 127:932-943. [PMID: 36655844 DOI: 10.1021/acs.jpcb.2c07060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The effects of limited amounts (under 21.6% χWater) of water on 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF4) and 1-butyl-3-methylimidazolium dicyanamide (BmimDCA) room-temperature ionic liquid (RTIL) mixtures were characterized by tracking changes in the linear and two-dimensional infrared (2D IR) vibrational features of the dicyanamide anion (DCA). Peak shifts with increasing water suggest the formation of water-associated and nonwater-associated DCA populations. Further results showed clear differences in the dynamic behavior of these different populations of DCA at low (defined here as below 2.5% χWater), mid (defined here as between 2.5% χWater and 9.6% χWater), and high (defined here as between 11.6% χWater and 21.6% χWater) range water concentrations. Vibrational relaxation is accelerated with increasing water content for water-associated populations of DCA, indicating water facilitates population relaxation, possibly through the provision of additional bath modes. Conversely, spectral diffusion of water-associated populations slowed dramatically with increasing water, suggesting that water drives the formation of distinct and noninterchangeable or very slowly interchangeable local solvent environments.
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Affiliation(s)
- Clara A Tibbetts
- Department of Chemistry, Colorado State University, Fort Collins, Colorado80523-1972, United States
| | - Autumn B Wyatt
- Department of Chemistry, Colorado State University, Fort Collins, Colorado80523-1972, United States
| | - Bradley M Luther
- Department of Chemistry, Colorado State University, Fort Collins, Colorado80523-1972, United States
| | - Anthony K Rappé
- Department of Chemistry, Colorado State University, Fort Collins, Colorado80523-1972, United States
| | - Amber T Krummel
- Department of Chemistry, Colorado State University, Fort Collins, Colorado80523-1972, United States
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4
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Ehrhard A, Gunkel L, Jäger S, Sell AC, Nagata Y, Hunger J. Elucidating Conformation and Hydrogen-Bonding Motifs of Reactive Thiourea Intermediates. ACS Catal 2022; 12:12689-12700. [PMID: 36313523 PMCID: PMC9594049 DOI: 10.1021/acscatal.2c03382] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/19/2022] [Indexed: 11/29/2022]
Abstract
Substituted diphenylthioureas (DPTUs) are efficient hydrogen-bonding organo-catalysts, and substitution of DPTUs has been shown to greatly affect catalytic activity. Yet, both the conformation of DPTUs in solution and the conformation and hydrogen-bonded motifs within catalytically active intermediates, pertinent to their mode of activation, have remained elusive. By combining linear and ultrafast vibrational spectroscopy with spectroscopic simulations and calculations, we show that different conformational states of thioureas give rise to distinctively different N-H stretching bands in the infrared spectra. In the absence of hydrogen-bond-accepting substrates, we show that vibrational structure and dynamics are highly sensitive to the substitution of DPTUs with CF3 groups and to the interaction with the solvent environment, allowing for disentangling the different conformational states. In contrast to bare diphenylthiourea (0CF-DPTU), we find the catalytically superior CF3-substituted DPTU (4CF-DPTU) to favor the trans-trans conformation in solution, allowing for donating two hydrogen bonds to the reactive substrate. In the presence of a prototypical substrate, DPTUs in trans-trans conformation hydrogen bond to the substrate's C=O group, as evidenced by a red-shift of the N-H vibration. Yet, our time-resolved infrared experiments indicate that only one N-H group forms a strong hydrogen bond to the carbonyl moiety, while thiourea's second N-H group only weakly interacts with the substrate. Our data indicate that hydrogen-bond exchange between these N-H groups occurs on the timescale of a few picoseconds for 0CF-DPTU and is significantly accelerated upon CF3 substitution. Our results highlight the subtle interplay between conformational equilibria, bonding states, and bonding lifetimes in reactive intermediates in thiourea catalysis, which help rationalize their catalytic activity.
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Affiliation(s)
- Amelie
A. Ehrhard
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Lucas Gunkel
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Sebastian Jäger
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Arne C. Sell
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Yuki Nagata
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Johannes Hunger
- Max-Planck Institute for
Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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5
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Biswas A, Mallik BS. Multiple Ensembles of the Hydrogen-bonded Network in Ethylammonium Nitrate versus Water from Vibrational Spectral Dynamics of SCN- Probe. Chemphyschem 2022; 23:e202200497. [PMID: 35965410 DOI: 10.1002/cphc.202200497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/05/2022] [Indexed: 11/12/2022]
Abstract
We performed classical molecular dynamics simulations to monitor the structural interactions and ultrafast dynamical and spectral response in the protic ionic liquid, ethylammonium nitrate (EAN) and water using the nitrile stretching mode of thiocyanate ion (SCN-) as the vibrational probe. The normalized stretch frequency distribution of nitrile stretch of SCN- attains an asymmetric shape in EAN, indicating the existence of more than one hydrogen-bonding environment in EAN. We computed the 2D IR spectrum from classical trajectories, applying the response function formalism. Spectral diffusion dynamics in EAN undergo an initial rattling of the SCN - inside the local ion-cage occurring at a timescale of 0.10 ps, followed by the breakup of the ion-cage activating molecular diffusion at 7.86 ps timescale. In contrast, the dynamics of structural reorganization occur at a timescale of 0.58 ps in H 2 O. Hence, the time dependence of the frequency-frequency correlation function decay hints at the local molecular structure and ultrafast ion dynamics of the SCN - probe. The loss of frequency correlation read from the peak shape changes in the 2D correlation spectrum as a function of waiting time is faster in H 2 O than in EAN due to the enhanced structural ordering and higher viscosity of the latter. We provide an atomic-level interpretation of the solvation environment around SCN - in EAN and water, which indicates the multiple ensembles of the hydrogen bond network in EAN.
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Affiliation(s)
- Aritri Biswas
- IITH: Indian Institute of Technology Hyderabad, Chemistry, INDIA
| | - Bhabani S Mallik
- IITH: Indian Institute of Technology Hyderabad, Chemistry, Kandi, 502285, Sangareddy, INDIA
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Yamada H, Stemo G, Katsuki H, Yanagi H. Development of a Spacerless Flow-Cell Cavity for Vibrational Polaritons. J Phys Chem B 2022; 126:4689-4696. [PMID: 35723438 DOI: 10.1021/acs.jpcb.2c02752] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We developed a spacerless flow-cell cavity for the observation of vibrational strong coupling and demonstrate its availability in two samples with a C≡N bond: a metal complex (aq) and an ionic liquid. It is shown that the cavity length can be tuned over a wide range to investigate coupling with different order Fabry-Pérot cavity modes without reassembling the cavity. In the ionic liquid, analyses based on the coupled harmonic oscillator model with multiple vibrational modes show that the Rabi splitting parameters and the square root of the integrated absorption intensity are proportional among the three neighboring vibrational modes. Our spacerless cell structure simplifies the comparison of the different vibrational strong coupling measurements, such as the mode order dependence and the coupling to different molecular vibrations.
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Affiliation(s)
- Hayata Yamada
- Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Garrek Stemo
- Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Hiroyuki Katsuki
- Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma 630-0192, Japan
| | - Hisao Yanagi
- Graduate School of Science and Technology, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma 630-0192, Japan
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7
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Biswas A, Mallik BS. Vibrational Spectral Dynamics and Ion-Probe Interactions of the Hydrogen-Bonded Liquids in 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. Chem Phys 2022. [DOI: 10.1016/j.chemphys.2022.111519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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8
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Biswas A, Mallik BS. Revisiting OD-stretching dynamics of methanol‑d4, ethanol-d6 and dilute HOD/H2O mixture with predefined potentials and wavelet transform spectra. Chem Phys 2022. [DOI: 10.1016/j.chemphys.2021.111385] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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9
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Weiß N, Thielemann G, Nagel K, Schmidt CH, Seifert A, Kaßner L, Strehmel V, Corzilius B, Schröder C, Spange S. The influence of the cation structure on the basicity-related polarity of ionic liquids. Phys Chem Chem Phys 2021; 23:26750-26760. [PMID: 34846390 DOI: 10.1039/d1cp03986e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UV/Vis absorption data of (E)-4-(2-[5-{4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl}thiene-2-yl]vinyl)-2-(dicyano-methylene)-3-cyano-5,5-dimethyl-2,5-dihydrofuran (ThTCF) as a solvatochromic probe is applied to examine the anion coordination strength (e.g. of N(CN)2, BF4, PF6, N(Tf)2, CF3COO) as a function of the cation structure of ionic liquids. Several 1-n-alky-3-methylimidazolium- and tetraalkylammonium CH3-NR3+-based ILs with different n-alkyl chain lengths (R = -C4H9, -C6H11, -C8H17, -C10H21) are considered. UV/Vis absorption data of ThTCF show subtle correlations with hydrogen bond accepting (HBA) ability-related measurands such as Kamlet-Taft β, Freire's EHB, and Laurence β1 parameter as a function of anion and cation structure. The different influence of the n-alkyl chain length of imidazolium- and tetraalkylammonium-based ILs on the dipolarity and HBA strength is confirmed by comparison with the 14N isotropic hyperfine coupling constants (Aiso) of a positively (CATI) and negatively charged spin probe (TSKCr) of TEMPO-type [(2,2,6,6-tetramethylpiperidin-1-yl)oxyl] and quantum chemically derived dipoles of the cations. The Aiso values correlate with the absorption energy of ThTCF and EHB, but in different ways depending on the anion or charge of the spin probe. In a final discussion of the β, EHB, and β1 scales in relation to ThTCF, the importance of the molar concentration N of ionic liquids for the physical significance of the respective parameters is discussed.
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Affiliation(s)
- Nadine Weiß
- Department of Polymer Chemistry, Institute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Gabi Thielemann
- Department of Polymer Chemistry, Institute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Kevin Nagel
- Department of Polymer Chemistry, Institute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Caroline H Schmidt
- Department of Polymer Chemistry, Institute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Andreas Seifert
- Department of Polymer Chemistry, Institute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Lysann Kaßner
- Department of Polymer Chemistry, Institute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
| | - Veronika Strehmel
- Department of Chemistry, Organic Chemistry and Institute for Coatings and Surface Chemistry, Hochschule Niederrhein, University of Applied Sciences, Adlerstraße 32, 47798 Krefeld, Germany.
| | - Björn Corzilius
- Institute of Chemistry, University Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany.
| | - Christian Schröder
- Institute of Computational Biological Chemistry, University of Vienna, Währingerstr. 17, 1090 Vienna, Austria.
| | - Stefan Spange
- Department of Polymer Chemistry, Institute of Chemistry, Chemnitz University of Technology, Straße der Nationen 62, 09111 Chemnitz, Germany.
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10
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Gorbunova IA, Sasin ME, Beltukov YM, Semenov AA, Vasyutinskii OS. Anisotropic relaxation in NADH excited states studied by polarization-modulation pump-probe transient spectroscopy. Phys Chem Chem Phys 2020; 22:18155-18168. [PMID: 32766648 DOI: 10.1039/d0cp02496a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We present the results of experimental and theoretical studies of fast anisotropic relaxation and rotational diffusion in the first electron excited state of biological coenzyme NADH in water-ethanol solutions. The experiments have been carried out by means of a novel polarization-modulation transient method and fluorescence polarization spectroscopy. For interpretation of the experimental results a model of the anisotropic relaxation in terms of scalar and vector properties of transition dipole moments has been developed based on the Born-Oppenheimer approximation. This model allows for the description of fast isotropic and anisotropic excited state relaxation under excitation of molecules by ultrafast laser pulses in transient absorption and upconversion experiments. The results obtained suggest that the dynamics of anisotropic rovibronic relaxation in NADH under excitation with 100 fs pump laser pulses can be characterised by a single vibrational relaxation time τv lying in the range of 2-15 ps and a single rotation diffusion time τr lying in the range of 100-450 ps, both depending on ethanol concentration. The dependence of the times τv and τr on the solution polarity (static permittivity) and viscosity has been determined and analyzed. Limiting values of the term P2(cos θ) describing the rotation of the transition dipole moment in the course of vibrational relaxation have been determined from experiments as a function of ethanol concentration and analyzed.
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Affiliation(s)
| | - Maxim E Sasin
- Ioffe Institute, Polytekhnicheskaya 26, St. Petersburg, Russia.
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11
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Biswas A, Mallik BS. Ultrafast Aqueous Dynamics in Concentrated Electrolytic Solutions of Lithium Salt and Ionic Liquid. J Phys Chem B 2020; 124:9898-9912. [DOI: 10.1021/acs.jpcb.0c06221] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Aritri Biswas
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy 502285, Telangana, India
| | - Bhabani S. Mallik
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy 502285, Telangana, India
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12
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Guchhait B, Tibbetts CA, Tracy KM, Luther BM, Krummel AT. Ultrafast vibrational dynamics of a trigonal planar anionic probe in ionic liquids (ILs): A two-dimensional infrared (2DIR) spectroscopic investigation. J Chem Phys 2020; 152:164501. [PMID: 32357764 DOI: 10.1063/1.5141751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A major impediment limiting the widespread application of ionic liquids (ILs) is their high shear viscosity. Incorporation of a tricyanomethanide (TCM-) anion in ILs leads to low shear viscosity and improvement of several characteristics suitable for large scale applications. However, properties including interactions of TCM- with the local environment and dynamics of TCM- have not been thoroughly investigated. Herein, we have studied the ultrafast dynamics of TCM- in several imidazolium ILs using linear IR and two-dimensional infrared spectroscopy techniques. The spectral diffusion dynamics of the CN stretching modes of TCM- in all ILs exhibit a nonexponential behavior with a short time component of ∼2 ps and a long time component spanning ∼9 ps to 14 ps. The TCM- vibrational probe reports a significantly faster relaxation of ILs compared to those observed previously using linear vibrational probes, such as thiocyanate and selenocyanate. Our results indicate a rapid relaxation of the local ion-cage structure embedding the vibrational probe in the ILs. The faster relaxation suggests that the lifetime of the local ion-cage structure decreases in the presence of TCM- in the ILs. Linear IR spectroscopic results show that the hydrogen-bonding interaction between TCM- and imidazolium cations in ILs is much weaker. Shorter ion-cage lifetimes together with weaker hydrogen-bonding interactions account for the low shear viscosity of TCM- based ILs compared to commonly used ILs. In addition, this study demonstrates that TCM- can be used as a potential vibrational reporter to study the structure and dynamics of ILs and other molecular systems.
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Affiliation(s)
- Biswajit Guchhait
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Clara A Tibbetts
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Kathryn M Tracy
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Bradley M Luther
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Amber T Krummel
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, USA
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13
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Curry JN, Shaw SK. Thermotropic Phase Transitions in Butyltrimethylammonium Bis(trifluoromethylsulfonyl)imide Ionic Liquids are Dependent on Heat Flux. J Phys Chem B 2019; 123:4757-4765. [DOI: 10.1021/acs.jpcb.9b01650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jaclyn N. Curry
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52245, United States
| | - Scott K. Shaw
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52245, United States
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