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Kim HJ. Spectroscopic and Chemical Properties of Ionic Liquids: Computational Study. CHEM REC 2023; 23:e202300075. [PMID: 37166396 DOI: 10.1002/tcr.202300075] [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: 02/27/2023] [Revised: 04/18/2023] [Indexed: 05/12/2023]
Abstract
A brief account is given of highlights of our computational efforts - often in collaboration with experimental groups - to understand spectroscopic and chemical properties of ionic liquids (ILs). Molecular dynamics, including their inhomogeneous character, responsible for key spectral features observed in dielectric absorption, infra-red (IR) and fluorescence correlation spectroscopy (FCS) measurements are elucidated. Mechanisms of chemical processes involving imidazolium-based ILs are illustrated for CO2 capture and related reactions, transesterification of cellulose, and Au nanocluster-catalyzed Suzuki cross-coupling reaction with attention paid to differing roles of IL ions. A comparison with experiments is also made.
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Affiliation(s)
- Hyung J Kim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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2
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Wei J, Liu Y, Song F. Coarse-grained simulation of the translational and rotational diffusion of globular proteins by dissipative particle dynamics. J Chem Phys 2020; 153:234902. [PMID: 33353321 DOI: 10.1063/5.0025620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
With simplified interactions and degrees of freedom, coarse-grained (CG) simulations have been successfully applied to study the translational and rotational diffusion of proteins in solution. However, in order to reach larger lengths and longer timescales, many CG simulations employ an oversimplified model for proteins or an implicit-solvent model in which the hydrodynamic interactions are ignored, and thus, the real kinetics are more or less unfaithful. In this work, we develop a CG model based on the dissipative particle dynamics (DPD) that can be universally applied to different types of proteins. The proteins are modeled as a group of rigid DPD beads without conformational changes. The fluids (including solvent and ions) are also modeled as DPD beads. The electrostatic interactions between charged species are explicitly considered by including charge distributions on DPD particles. Moreover, a surface friction between the protein and fluid beads is applied to control the slip boundary condition. With this model, we investigate the self-diffusion of a single globular protein in bulk solution. The translational and rotational diffusion coefficients of the protein can be tuned by the surface frictional constant to fit the predictions of the Stokes-Einstein (SE) relation. We find that both translational and rotational diffusion coefficients that meet with the prediction of the SE relation based on experimental results of the hydrodynamic radius are reached at almost the same frictional constant for different types of proteins. Such scaling behavior indicates that the model can be applied to simulate the translational and rotational diffusion together for various types of proteins.
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Affiliation(s)
- Jiachen Wei
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yawei Liu
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Fan Song
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
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3
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Polok K, Beisert M, Swiątek A, Maity N, Piatkowski P, Gadomski W, Miannay FA, Idrissi A. Dynamics in the BMIM PF 6/acetonitrile mixtures observed by femtosecond optical Kerr effect and molecular dynamics simulations. Phys Chem Chem Phys 2020; 22:24544-24554. [PMID: 33094298 DOI: 10.1039/d0cp03847d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have performed the measurements of the optical Kerr effect signal time evolution up to 4 ns for a mixture of 1-alkyl-3-methyl-imidazolium hexafluorophosphate (BMIM PF6) ionic liquid and acetonitrile in the whole mole fractions range. The long delay line in our experimental setup allowed us to capture the complete reorientational dynamics of the ionic liquid. We have analysed the optical Kerr effect signal in the time and frequency domains with help of molecular dynamics simulations. In our approximation of the slow picosecond dynamics with a multi-exponential decay, we distinguish three relaxation times. The highest two are assigned to the reorientation of the cation and acetonitrile molecules that are in the vicinity of the imidazolium ring. The third one is recognized as originating from cation rotations and reorientation of acetonitrile molecules in the bulk or in the vicinity of the aliphatic chains of the cation. With help of the simulation we interpret the intermolecular band in the reduced spectral density, obtained from Kerr signal, as follows: its low-frequency side results from oscillations of one of the components in the cage formed by its neighbors, while the high-frequency side is attributed to the librations of the cation and acetonitrile molecule as well as the intermolecular oscillations of system components involved in specific interactions. We use this assignment and concentration dependence of the spectra obtained from velocity and angular velocity correlations to explain the mole fraction dependence of Kerr reduced spectral density.
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Affiliation(s)
- Kamil Polok
- Faculty of Chemistry, Laboratory of Spectroscopy and Intermolecular Interactions, University of Warsaw, Żwirki i Wigury 101, Warsaw 02-089, Poland.
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Haridasan N, Kannam SK, Mogurampelly S, Sathian SP. Rotational Diffusion of Proteins in Nanochannels. J Phys Chem B 2019; 123:4825-4832. [DOI: 10.1021/acs.jpcb.9b00895] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Navaneeth Haridasan
- Micro and Nanoscale Transport Lab, Applied Mechanics Department, Indian Institute of Technology Madras, Chennai 600036, India
| | - Sridhar Kumar Kannam
- Department of Mathematics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia
- School of Sciences, RMIT University, Melbourne, Victoria 3001, Australia
| | - Santosh Mogurampelly
- Institute for Computational Molecular Science, Temple University, Philadelphia 19122, United States
- Department of Physics, Indian Institute of Technology Jodhpur, Rajasthan 342037, India
| | - Sarith P Sathian
- Micro and Nanoscale Transport Lab, Applied Mechanics Department, Indian Institute of Technology Madras, Chennai 600036, India
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Heid E, Schröder C. Polarizability in ionic liquid simulations causes hidden breakdown of linear response theory. Phys Chem Chem Phys 2019; 21:1023-1028. [PMID: 30601488 DOI: 10.1039/c8cp06569a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The validity of linear response theory (LRT) in computer simulations of solvation dynamics, i.e. the time-dependent Stokes shift, has been debated widely during the last decades. Since the use of LRT is computationally less expensive than the calculation of the true nonequilibrium response, it is often invoked for large systems exhibiting a particularly slow solvation response, e.g. ionic liquids. In the case of ionic liquids, LRT does not only need to capture the correct overall dynamics of the system, but also the contributions and timescales of the respective cation and anion movement. We show by large scale computer simulations that the contribution of the permanent dipoles to the solvation response obeys LRT to some extent, whereas the induced contributions in polarizable simulations lead to a failure of LRT for the respective ion contributions.
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Affiliation(s)
- Esther Heid
- University of Vienna, Faculty of Chemistry, Department of Computational Biological Chemistry, Währingerstraße 19, A-1090 Vienna, Austria.
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Liu J, Willcox JAL, Kim HJ. Heterogeneous dynamics of ionic liquids: A four-point time correlation function approach. J Chem Phys 2018; 148:193830. [DOI: 10.1063/1.5016501] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jiannan Liu
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, Pennsylvania 15213, USA
| | - Jon A. L. Willcox
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, Pennsylvania 15213, USA
| | - Hyung J. Kim
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave., Pittsburgh, Pennsylvania 15213, USA
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, South Korea
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Heid E, Schröder C. Solvation dynamics in polar solvents and imidazolium ionic liquids: failure of linear response approximations. Phys Chem Chem Phys 2018; 20:5246-5255. [PMID: 29400383 PMCID: PMC5815284 DOI: 10.1039/c7cp07052g] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/19/2018] [Indexed: 12/18/2022]
Abstract
This study presents the large scale computer simulations of two common fluorophores, N-methyl-6-oxyquinolinium betaine and coumarin 153, in five polar or ionic solvents. The validity of linear response approximations to calculate the time-dependent Stokes shift is evaluated in each system. In most studied systems linear response theory fails. In ionic liquids the magnitude of the overall response is largely overestimated, and linear response theory is not able to capture the individual contributions of cations and anions. In polar liquids, the timescales of solvation dynamics are often not correctly reproduced. These observations are complemented by a detailed analysis of Gaussian statistics including higher order correlation functions, variance of the energy gap distribution and its time evolution. The analysis of higher order correlation functions was found to be not suitable to predict a failure of linear response theory. Further analysis of radial distribution functions and hydrogen bonds in the ground and excited state, as well as the time evolution of the number of hydrogen bonds after solute excitation reveal an influence of solvent structure in some of the studied systems.
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Affiliation(s)
- Esther Heid
- University of Vienna , Faculty of Chemistry , Department of Computational Biological Chemistry , Währingerstraße 19 , A-1090 Vienna , Austria . ; Tel: +43 14277 52711
| | - Christian Schröder
- University of Vienna , Faculty of Chemistry , Department of Computational Biological Chemistry , Währingerstraße 19 , A-1090 Vienna , Austria . ; Tel: +43 14277 52711
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Willcox JAL, Kim H, Kim HJ. A molecular dynamics study of the ionic liquid, choline acetate. Phys Chem Chem Phys 2017; 18:14850-8. [PMID: 27188287 DOI: 10.1039/c6cp01031h] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structural and dynamic properties of the ionic liquid (IL) choline acetate are studied using molecular dynamics (MD) simulations. The hydroxyl group of choline shows significant hydrogen-bonding interactions with the oxygen atoms of acetate. Nearly all choline cations are found to form a hydrogen bond with acetate anions at 400 K, while about 67% of cations participate in hydrogen-bonding interactions at 600 K. At 400 K, subdiffusive and prominent non-Gaussian behavior persist for t > 10 ns. At 600 K, the usual diffusion regime is obtained after a few hundred ps of subdiffusive behavior. Analysis of reorientational motions of acetate ions, particularly those of their short axes, indicates a high degree of dynamic heterogeneity, in agreement with previous work on different IL systems.
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Affiliation(s)
- Jon A L Willcox
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave, Pittsburgh, PA 15213, USA.
| | - Hyunjin Kim
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave, Pittsburgh, PA 15213, USA.
| | - Hyung J Kim
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Ave, Pittsburgh, PA 15213, USA. and School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Korea
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9
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Rumble CA, Uitvlugt C, Conway B, Maroncelli M. Solute Rotation in Ionic Liquids: Size, Shape, and Electrostatic Effects. J Phys Chem B 2017; 121:5094-5109. [DOI: 10.1021/acs.jpcb.7b01704] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher A. Rumble
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Caleb Uitvlugt
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Brian Conway
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mark Maroncelli
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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10
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Rumble CA, Kaintz A, Yadav SK, Conway B, Araque JC, Baker GA, Margulis C, Maroncelli M. Rotational Dynamics in Ionic Liquids from NMR Relaxation Experiments and Simulations: Benzene and 1-Ethyl-3-Methylimidazolium. J Phys Chem B 2016; 120:9450-67. [DOI: 10.1021/acs.jpcb.6b06715] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christopher A. Rumble
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Anne Kaintz
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Sharad K. Yadav
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Brian Conway
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Juan C. Araque
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Gary A. Baker
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Claudio Margulis
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Mark Maroncelli
- Department
of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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11
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Araque JC, Daly RP, Margulis CJ. A link between structure, diffusion and rotations of hydrogen bonding tracers in ionic liquids. J Chem Phys 2016; 144:204504. [DOI: 10.1063/1.4951012] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Juan C. Araque
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA
| | - Ryan P. Daly
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA
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12
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Kim D, Jeong D, Jung Y. Dynamic propensity as an indicator of heterogeneity in room-temperature ionic liquids. Phys Chem Chem Phys 2014; 16:19712-9. [DOI: 10.1039/c4cp01893a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dynamic propensity of an RTIL system exhibits broad and asymmetric distributions, and spatial patterns of the dynamic propensity and mobility distribution are shown.
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Affiliation(s)
- Daekeon Kim
- Department of Chemistry
- Seoul National University
- Seoul, Korea
| | - Daun Jeong
- Department of Chemistry
- Seoul National University
- Seoul, Korea
| | - YounJoon Jung
- Department of Chemistry
- Seoul National University
- Seoul, Korea
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13
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Długosz M, Antosiewicz JM. Evaluation of Proteins’ Rotational Diffusion Coefficients from Simulations of Their Free Brownian Motion in Volume-Occupied Environments. J Chem Theory Comput 2013; 10:481-91. [DOI: 10.1021/ct4008519] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Maciej Długosz
- Center of New Technologies and ‡Department of Biophysics, Faculty of Physics, University of Warsaw, Żwirki i Wigury 93, Warsaw 02-089, Poland
| | - Jan M. Antosiewicz
- Center of New Technologies and ‡Department of Biophysics, Faculty of Physics, University of Warsaw, Żwirki i Wigury 93, Warsaw 02-089, Poland
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14
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Wright LB, Freeman CL, Walsh TR. Benzene adsorption at the aqueous (0 1 1) α-quartz interface: is surface flexibility important? MOLECULAR SIMULATION 2013. [DOI: 10.1080/08927022.2013.796589] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Daschakraborty S, Pal T, Biswas R. Stokes shift dynamics of ionic liquids: Solute probe dependence, and effects of self-motion, dielectric relaxation frequency window, and collective intermolecular solvent modes. J Chem Phys 2013; 139:164503. [DOI: 10.1063/1.4825195] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Daschakraborty S, Biswas R. Ultrafast solvation response in room temperature ionic liquids: Possible origin and importance of the collective and the nearest neighbour solvent modes. J Chem Phys 2012; 137:114501. [DOI: 10.1063/1.4752425] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Roy D, Maroncelli M. Simulations of Solvation and Solvation Dynamics in an Idealized Ionic Liquid Model. J Phys Chem B 2012; 116:5951-70. [DOI: 10.1021/jp301359w] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Durba Roy
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802,
United States
| | - Mark Maroncelli
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802,
United States
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18
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Maroncelli M, Zhang XX, Liang M, Roy D, Ernsting NP. Measurements of the complete solvation response of coumarin 153 in ionic liquids and the accuracy of simple dielectric continuum predictions. Faraday Discuss 2012; 154:409-24; discussion 439-64, 465-71. [DOI: 10.1039/c1fd00058f] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Khara DC, Samanta A. Fluorescence, Phosphorescence, and Delayed Fluorescence of Benzil in Imidazolium Ionic Liquids. Aust J Chem 2012. [DOI: 10.1071/ch12066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Temperature dependence of the emission behaviour of benzil has been studied in three imidazolium ionic liquids differing in their polarity and viscosity. Room temperature absorption and steady-state emission spectra suggest that the ground and excited state conformers of benzil in ionic liquids are similar to those in conventional organic solvents. The non-degassed solutions of benzil in ionic liquids show phosphorescence at room temperature in contrast to conventional solvents where phosphorescence is commonly observed in degassed conditions. This study reveals that a thermally activated reverse intersystem crossing (T1↝S1) process is responsible for the drastic change in phosphorescence intensity with temperature in ionic liquids. The rate constant () of this process is found to be dependent on the polarity of the media and is 5 times higher in most polar ionic liquids. The evidence of the presence of multiple conformers of benzil in frozen conditions is obtained from the excitation wavelength dependence of the phosphorescence spectra.
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Klein ML. Communication: Exploring the reorientation of benzene in an ionic liquid via molecular dynamics: Effect of temperature and solvent effective charge on the slow dynamics. J Chem Phys 2011; 134:191101. [DOI: 10.1063/1.3592530] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Miyake Y, Akai N, Kawai A, Shibuya K. Hydrodynamic Interpretation on the Rotational Diffusion of Peroxylamine Disulfonate Solute Dissolved in Room Temperature Ionic Liquids As Studied by Electron Paramagnetic Resonance Spectroscopy. J Phys Chem A 2011; 115:6347-56. [DOI: 10.1021/jp112151d] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Yusuke Miyake
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 H57 Ohokayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Nobuyuki Akai
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 H57 Ohokayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Akio Kawai
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 H57 Ohokayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Kazuhiko Shibuya
- Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 H57 Ohokayama, Meguro-ku, Tokyo 152-8551, Japan
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22
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Shim Y, Jung Y, Kim HJ. Carbon nanotubes in benzene: internal and external solvation. Phys Chem Chem Phys 2011; 13:3969-78. [DOI: 10.1039/c0cp01845g] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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23
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Shim Y, Kim HJ. MD Study of Solvation in the Mixture of a Room-Temperature Ionic Liquid and CO2. J Phys Chem B 2010; 114:10160-70. [DOI: 10.1021/jp105021b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Youngseon Shim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Department of Chemistry, Seoul National University, Seoul 151-747, Korea, and School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-722, Korea
| | - Hyung J. Kim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Department of Chemistry, Seoul National University, Seoul 151-747, Korea, and School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-722, Korea
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24
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Roy D, Patel N, Conte S, Maroncelli M. Dynamics in an Idealized Ionic Liquid Model. J Phys Chem B 2010; 114:8410-24. [DOI: 10.1021/jp1004709] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Durba Roy
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Nikhil Patel
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Sean Conte
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Mark Maroncelli
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
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Jeong D, Choi MY, Kim HJ, Jung Y. Fragility, Stokes–Einstein violation, and correlated local excitations in a coarse-grained model of an ionic liquid. Phys Chem Chem Phys 2010; 12:2001-10. [DOI: 10.1039/b921725h] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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27
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Song X. Solvation dynamics in ionic fluids: An extended Debye–Hückel dielectric continuum model. J Chem Phys 2009; 131:044503. [DOI: 10.1063/1.3187147] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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28
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Shim Y, Kim HJ. Dielectric Relaxation, Ion Conductivity, Solvent Rotation, and Solvation Dynamics in a Room-Temperature Ionic Liquid. J Phys Chem B 2008; 112:11028-38. [DOI: 10.1021/jp802595r] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Youngseon Shim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, and School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-722, Korea
| | - Hyung J. Kim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, and School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-722, Korea
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29
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Jeong D, Choi MY, Jung Y, Kim HJ. 1∕f spectrum and memory function analysis of solvation dynamics in a room-temperature ionic liquid. J Chem Phys 2008; 128:174504. [DOI: 10.1063/1.2911927] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Jin H, Li X, Maroncelli M. Heterogeneous Solute Dynamics in Room Temperature Ionic Liquids. J Phys Chem B 2007; 111:13473-8. [DOI: 10.1021/jp077226+] [Citation(s) in RCA: 178] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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32
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Shim Y, Kim HJ. Free Energy and Dynamics of Electron-Transfer Reactions in a Room Temperature Ionic Liquid. J Phys Chem B 2007; 111:4510-9. [PMID: 17425362 DOI: 10.1021/jp0703859] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Reaction free energetics and dynamics of unimolecular electron-transfer processes in ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate (EMI+PF6-) are investigated via molecular dynamics computer simulations employing a model diatomic solute and compared with those in aprotic acetonitrile. Using the free energy perturbation method, diabatic free energy curves relevant to charge separation and recombination processes are studied over a wide range of the reaction coordinate. The diabatic curves are found to vary with the solute charge distribution, especially in EMI+PF6-. Nevertheless, if the free energy of reaction is not that substantial, the Marcus free energy relationship holds reasonably well, provided that the reorganization free energy averaged between the reactant and product states is employed. The effective polarity, measured as solvation-induced stabilization of dipolar solutes, is higher for EMI+PF6- than for acetonitrile, consonant with many solvatochromic measurements. Thus, in the normal regime, activation barriers for charge separation and recombination reactions are, respectively, lower and higher in EMI+PF6- than in acetonitrile. The influence of solvent dynamics on reaction kinetics through modulations of activation, deactivation, and barrier crossing is analyzed. Even though overall solvent relaxation dynamics in EMI+PF6- are considerably slower than those in acetonitrile, the deviation of the rate constant from the transition state theory predictions is found to be small for both solvents. Implications of this finding for other reactions in ionic liquids are briefly discussed.
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Affiliation(s)
- Youngseon Shim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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Arzhantsev S, Jin H, Baker GA, Maroncelli M. Measurements of the Complete Solvation Response in Ionic Liquids. J Phys Chem B 2007; 111:4978-89. [PMID: 17319715 DOI: 10.1021/jp067273m] [Citation(s) in RCA: 207] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Dynamic Stokes shift measurements of the solvatochromic probe trans-4-dimethylamino-4'-cyanostilbene were used to measure the solvation response of five imidazolium and one pyrrolidinium ionic liquid at 25 degrees C. The Kerr-gated emission and time-correlated single-photon-counting techniques were used to measure spectral dynamics occurring over the time ranges of 100 fs-200 ps and 50 ps-5 ns, respectively, and a combination of data sets from these two techniques enabled observation of the complete solvation response. Observed response functions were found to be biphasic, consisting of a sub-picosecond component of modest (10-20%) amplitude and a dominant slower component relaxing over times of a few picoseconds to several nanoseconds. The faster component could be correlated to inertial characteristics of the constituent ions, and the slower component to solvent viscosity. Dielectric continuum calculations of the sort previously used to predict solvation dynamics in dipolar liquids were shown to work poorly for predicting the response in these ionic liquids.
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Affiliation(s)
- Sergei Arzhantsev
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, USA
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Jeong D, Shim Y, Choi MY, Kim HJ. Effects of Solute Electronic Polarizability on Solvation in a Room-Temperature Ionic Liquid. J Phys Chem B 2007; 111:4920-5. [PMID: 17253742 DOI: 10.1021/jp067316z] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of solute polarizability on solvation and solute transport in the room-temperature ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate (EMI+PF(6)-) are investigated via molecular dynamics simulations. A valence-bond description is employed to account for the instantaneous adjustment of the solute electronic charge distribution to the fluctuating solvent environment. It is found that the ultrafast inertial component of solvation dynamics becomes slower as the solute polarizability grows. Moreover, its contribution to overall solvent relaxation becomes reduced with increasing polarizability, especially in the case of nonequilibrium solvation dynamics. Overall, the inclusion of the solute electronic polarizability in the simulations improves the agreement with time-dependent Stokes shift measurements.
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Affiliation(s)
- Daun Jeong
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
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