1
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Simonis ED, Blanchard GJ. Evaluating the contributions to conductivity in room temperature ionic liquids. Phys Chem Chem Phys 2024; 26:17048-17056. [PMID: 38836605 DOI: 10.1039/d4cp01218f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
The conductivity of room temperature ionic liquids is not described adequately by the Nernst-Einstein equation, which accounts only for Brownian motion of the ions. We report on the conductivity of the ionic liquid 1-butyl-3-methylimidazolum bis(trifluoromethylsulfonyl) imide (BMIM TFSI), comparing the known conductivity of this RTIL to the diffusion constants of the cationic and anionic species over a range of length scales, using time-resolved fluorescence depolarization and fluorescence recovery after photobleaching (FRAP) measurements of chromophores in the RTIL. Our data demonstrate that the diffusional contribution to molar conductivity is ca. 50%. Another mechanism for the transmission of charged species in RTILs is responsible for the "excess" molar conductivity, and we consider possible contributions.
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Affiliation(s)
- Emily D Simonis
- Michigan State University, Department of Chemistry, 578 S. Shaw Lane, East Lansing, MI 48824, USA.
| | - G J Blanchard
- Michigan State University, Department of Chemistry, 578 S. Shaw Lane, East Lansing, MI 48824, USA.
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2
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Morichika I, Tsusaka H, Ashihara S. Generation of High-Lying Vibrational States in Carbon Dioxide through Coherent Ladder Climbing. J Phys Chem Lett 2024; 15:4662-4668. [PMID: 38647557 PMCID: PMC11073050 DOI: 10.1021/acs.jpclett.4c00646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024]
Abstract
Mid-infrared laser excitation of molecules into high-lying vibrational states offers a novel route to realize controlled ground-state chemistry. Here we successfully demonstrate vibrational ladder climbing in the antisymmetric stretch of CO2 in the condensed phase by using intense down-chirped mid-infrared pulses. Spectrally resolved pump-probe measurements directly observe excited-state absorptions attributed to vibrational populations up to the v = 9 state, whose corresponding energy of 2.5 eV is 46% of the dissociation energy. By the use of global fitting analysis, important spectroscopic parameters in the high-lying vibrational states, such as transition frequencies and relaxation times, are quantitatively characterized. Remarkably, our analysis shows that 40% of the molecules are excited above the typical activation barriers in the metal-catalyzed CO2 conversions. These results not only demonstrate the promising ability of infrared excitation to produce elevated vibrational states but also represent a significant step toward accelerating CO2 conversions and other chemical processes via mode-specific vibrational excitation.
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Affiliation(s)
- Ikki Morichika
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Hiroki Tsusaka
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Satoshi Ashihara
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
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3
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Hossain MI, Wang H, Adhikari L, Baker GA, Mezzetta A, Guazzelli L, Mussini P, Xie W, Blanchard GJ. Structure-Dependence and Mechanistic Insights into the Piezoelectric Effect in Ionic Liquids. J Phys Chem B 2024; 128:1495-1505. [PMID: 38301038 PMCID: PMC10961722 DOI: 10.1021/acs.jpcb.3c07967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 01/03/2024] [Accepted: 01/15/2024] [Indexed: 02/03/2024]
Abstract
We reported recently that two imidazolium room-temperature ionic liquids (RTILs) exhibit the direct piezoelectric effect (J. Phys. Chem. Lett., 2023, 14, 2731-2735). We have subsequently investigated several other RTILs with pyrrolidinium and imidazolium cations and tetrafluoroborate and bis(trifluoromethylsulfonyl)imide anions in an effort to gain insight into the generality and mechanism of the effect. All the RTILs studied exhibit the direct piezoelectric effect, with a magnitude (d33) and threshold force that depend on the structures of both the cation and anion. The structure-dependence and existence of a threshold force for the piezoelectric effect are consistent with a pressure-induced liquid-to-crystalline solid phase transition in the RTILs, and this is consistent with experimental X-ray diffraction data.
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Affiliation(s)
- Md. Iqbal Hossain
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Haozhe Wang
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Laxmi Adhikari
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Gary A. Baker
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Andrea Mezzetta
- Department
of Pharmacy, University of Pisa, Via Bonanno 33, 56126 Pisa, Italy
| | - Lorenzo Guazzelli
- Department
of Pharmacy, University of Pisa, Via Bonanno 33, 56126 Pisa, Italy
| | - Patrizia Mussini
- Department
of Chemistry, University of Milan, Via Golgi 19, 20133 Milano, Italy
| | - Weiwei Xie
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - G. J. Blanchard
- Department
of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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4
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Abstract
The piezoelectric effect was discovered over a century ago, and it has found wide application since that time. The direct piezoelectric effect is the production of charge upon application of force to a material, and the converse piezoelectric effect is a change in the material dimension(s) upon the application of a potential. To date, piezoelectric effects have been observed only in solid-phase materials. We report here the observation of the direct piezoelectric effect in room-temperature ionic liquids (RTILs). The RTILs 1-butyl-3-methyl imidazolium bis(trifluoromethyl-sulfonyl)imide (BMIM+TFSI-) and 1-hexyl-3-methyl imidazolium bis(trifluoromethylsulfonyl) imide (HMIM+TFSI-) produce a potential upon the application of force when confined in a cell, with the magnitude of the potential being directly proportional to the force applied. The effect is one order of magnitude smaller than that seen in quartz. This is the first report to our knowledge of the direct piezoelectric effect in a neat liquid. Its discovery has fundamental implications about the organization and dynamics in ionic liquids and invites theoretical treatment.
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Affiliation(s)
- Md Iqbal Hossain
- Michigan State University, Department of Chemistry, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - G J Blanchard
- Michigan State University, Department of Chemistry, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
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5
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Hossain MI, Adhikari L, Baker GA, Blanchard GJ. Relating the Induced Free Charge Density Gradient in a Room-Temperature Ionic Liquid to Molecular-Scale Organization. J Phys Chem B 2023; 127:1780-1788. [PMID: 36790441 DOI: 10.1021/acs.jpcb.2c07745] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
We report on dilution-dependent changes in the local environments of chromophores incorporated into room-temperature ionic liquid (RTIL)-molecular solvent binary systems where the ionic liquid cation and molecular solvent possess the same alkyl chain length. We have used the RTIL 1-decyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (DMPyrr+TFSI-) and the molecular solvent 1-decanol. Perylene was used as a non-polar probe, and cresyl violet (CV+) was used as a polar probe chromophore. We observe that in both regions there is a change in the chromophore local environments with increasing 1-decanol content. The changes in the nonpolar regions of the binary RTIL-molecular solvent system occur at a lower 1-decanol concentration than changes in the polar regions. Both chromophores reorient as oblate rotors in this binary system, allowing detailed information on the relative values of the Cartesian components of the rotational diffusion constants to be extracted from the experimental data. The induced free charge density gradient, ρf, known to exist in RTILs, persists to high 1-decanol content (1-decanol mole fraction of 0.75), with the structural details of the gradient being reflected in depth-dependent changes in the Cartesian components of the rotational diffusion constants of CV+. This is the first time that changes in molecular organization have been correlated with ρf.
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Affiliation(s)
- Md Iqbal Hossain
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
| | - Laxmi Adhikari
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Gary A Baker
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - G J Blanchard
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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6
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Said A, Liu C, Gao C, Wang D, Niu H, Liu Y, Wang G, Tung CH, Wang Y. Lead-Decorated Titanium Oxide Compound with a High Performance in Catalytic CO 2 Insertion to Epoxides. Inorg Chem 2023; 62:1901-1910. [PMID: 36184952 DOI: 10.1021/acs.inorgchem.2c01315] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The CO2 cycloaddition to epoxides is an efficient method for CO2 capture and storage, important not only for reducing greenhouse gas emission but also for producing cyclic carbonates, which are valuable industrial materials. In this study, we report a novel high-nuclearity titanium oxide cluster (TOC) inlayed with main-group element Pb2+, H2Ti16Pb9O24(SA)18(DMF)10(OH2)2 (denoted as 1; SA = salicylate; DMF = N,N-dimethylformamide), which has the property of visible-light absorption and has shown high catalytic activities for cycloadditions of CO2 under visible-light irradiation. The cluster was synthesized in a high yield in a facial solvothermal process. Its structure and electronic structure were characterized by single-crystal X-ray diffraction, density functional theory calculations, and complementary techniques. The cycloaddition reactions were performed under solvent-free conditions. While the catalytic activity due to the Lewis acidity was moderate, visible-light irradiation further folded the reaction rates. The turnover number reached 3400 with a turnover frequency of 120 h-1. Mechanism studies indicated a synergistic effect of the Lewis acidity and photogenerated charge carriers. The performance of 1 in reversible I2 uptake was also investigated. This study demonstrates the high potential of heterometal-decorated TOCs in the cost-effective and efficient CO2 cycloaddition reaction under mild conditions.
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Affiliation(s)
- Amir Said
- Key Laboratory for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Caiyun Liu
- Key Laboratory for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Chang Gao
- Key Laboratory for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Dexin Wang
- Key Laboratory for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Huihui Niu
- Key Laboratory for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Yanshu Liu
- Key Laboratory for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Guo Wang
- Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Chen-Ho Tung
- Key Laboratory for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
| | - Yifeng Wang
- Key Laboratory for Colloid and Interface Science of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China
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7
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Iqbal Hossain M, Blanchard G. Dilution-induced changes in room temperature ionic liquids. Persistent compositional heterogeneity and the importance of dipolar interactions. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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8
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Dicationic ionic liquids (DILs) based on the phenyl and perfluoro-phenyl π-spacer-linked triazolium cations: a quantum chemical comparative study. Theor Chem Acc 2022. [DOI: 10.1007/s00214-022-02931-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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9
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Biswas A, Mallik BS. Molecular Simulation-Guided Spectroscopy of Imidazolium-Based Ionic Liquids and Effects of Methylation on Ion-Cage and -Pair Dynamics. J Phys Chem B 2022; 126:8838-8850. [PMID: 36264223 DOI: 10.1021/acs.jpcb.2c04901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Classical molecular dynamics simulations were performed to assess an atomistic interpretation of the ion-probe structural interactions in two typical ionic liquids (ILs), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIm][NTf2] and 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide [BDimIm][NTf2] through computational ultrafast spectroscopy. The nitrile stretching vibrations of the thiocyanate anion, [SCN]-, serve as the local mode of the ultrafast system dynamics within the imidazolium-based ionic liquid environment. The wavelet transform of classical trajectories determines the time-varying fluctuating frequencies and the stretch spectral signatures of SCN- in the normalized distribution. However, computational modeling of the two-dimensional (2D) spectra from the wavelet-derived vibrational frequencies yields time evolution of the local molecular structure along with the varied time-dependent dynamics of the spectral diffusion process. We calculated the frequency-frequency correlation functions (FFCFs), time correlations associated with the ion-pair and -cage dynamics, and mean square displacements as a function of time, depicting diffusive dynamics. The calculated results based on the pair correlation functions and the distribution of atomic density suggest that the hydrogen and methylated carbon at the two-position of the imidazolium ring of [BMIm] and [BDimIm] cations, respectively, strongly interact with the probe through the N of the thiocyanate anion rather than the S atom. The center-of-mass center-of-mass (COM-COM) cation-probe radial distribution functions (RDFs) in conjunction with the site-specific structural analysis further reveal well-structured interactions of the thiocyanate ion and [BMIm]+ cation rather than the [BDimIm] cation. In contrast, the anion-probe COM-COM RDFs depict weak interactive associations within the vibrational probe [SCN]- and [NTf2]- ions. Methylation at the two-position of the imidazolium ring predicts slower structural reorganization and breaking and reformation dynamics of the ion pairs and cages within the ionic liquid framework.
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Affiliation(s)
- Aritri Biswas
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy502285, Telangana, India
| | - Bhabani S Mallik
- Department of Chemistry, Indian Institute of Technology Hyderabad, Sangareddy502285, Telangana, India
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10
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Karunaratne W, Zhao M, Castner EW, Margulis CJ. Vacuum Interfacial Structure and X-ray Reflectivity of Imidazolium-Based Ionic Liquids with Perfluorinated Anions from a Theory and Simulations Perspective. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:13936-13945. [PMID: 36017361 PMCID: PMC9394757 DOI: 10.1021/acs.jpcc.2c03311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/22/2022] [Indexed: 06/15/2023]
Abstract
We report studies of the vacuum interfacial structure of a series of 1-methyl-3-alkylimidazolium bis(perfluoroalkanesulfonyl)imide ionic liquids (ILs) and predict and explain their Fresnel-normalized X-ray reflectivity. To better interpret the results, we use a theory we recently developed dubbed "the peaks and antipeaks analysis of reflectivity" which splits the overall signal into that of different pair subcomponents. Whereas the overall reflectivity signal is not very informative, the peak and trough intensities for the pair subcomponents provide rich information for analysis. When species containing cationic alkyl or anionic fluoroalkyl tails are present at the interface, a tail layer is found next to a vacuum, and this tail layer can be composed of both alkyl and fluoroalkyl moieties. To maintain the positive-negative alternation of charged groups, alkyl and fluoroalkyl tails must necessarily be nearby and cannot segregate. Charged groups are found in the subsequent layer just below the interface and arranged to achieve lateral charge neutrality. In general, fluctuations at and away from the interface are based on polarity (i.e., heads and tails) and not on charge; when there are no significant alkyl or fluoroalkyl moieties in the IL, atomic density fluctuations away from the interface are small and appear to exist for the purpose of achieving lateral charge balance. For all the systems reported here, the persistence length of density fluctuations does not go beyond ∼7 nm.
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Affiliation(s)
| | - Man Zhao
- Department
of Chemistry and Chemical Biology, Rutgers,
The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Edward W. Castner
- Department
of Chemistry and Chemical Biology, Rutgers,
The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Claudio J. Margulis
- Department
of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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11
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Wang Y, Adhikari L, Baker GA, Blanchard GJ. Cation structure-dependence of the induced free charge density gradient in imidazolium and pyrrolidinium ionic liquids. Phys Chem Chem Phys 2022; 24:19314-19320. [PMID: 35929735 DOI: 10.1039/d2cp01066f] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on the structure-dependence and magnitude of the induced free charge density gradient (ρf) seen in room-temperature ionic liquids (RTILs) with imidazolium and pyrrolidinium cations. We characterize the spatially-resolved rotational diffusion dynamics of a trace-level cationic chromophore to characterize ρf in three different pyrrolidinium RTILs and two imidazolium RTILs. Our data show that the magnitude of ρf depends primarily on the alkyl chain length of RTIL cation and the persistence length of ρf is independent of RTILs' cation structure. These findings collectively suggest that mesoscopic structure in RTILs plays a significant role in allowing charge density gradients to form.
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Affiliation(s)
- Yufeng Wang
- Michigan State University, Department of Chemistry, East Lansing, MI 48824, USA.
| | - Laxmi Adhikari
- University of Missouri, Department of Chemistry, Columbia, MO 65211, USA
| | - Gary A Baker
- University of Missouri, Department of Chemistry, Columbia, MO 65211, USA
| | - G J Blanchard
- Michigan State University, Department of Chemistry, East Lansing, MI 48824, USA.
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12
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Wang Y, Adhikari L, Baker GA, Blanchard GJ. Cation structure-dependence of the Pockels effect in aprotic ionic liquids. Phys Chem Chem Phys 2022; 24:18067-18072. [PMID: 35861617 DOI: 10.1039/d2cp01068b] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on the dependence of surface charge-induced birefringence (the Pockels effect) in room temperature ionic liquids (RTILs) with different cation constituents. The induced birefringence is related to the induced free charge density gradient (ρf) in the RTIL. The RTILs are confined in a lens-shaped cell and the surface charge density of the concave cell surface is controlled by the current passed through the surface ITO film. We find that, in all cases, the induced birefringence is proportional to the surface charge density and that the change in refractive index nearest the ITO surface can be on the order of 20%. Our findings indicate that the induced birefringence depends more sensitively on the cation aliphatic substituent length than on the identity of the charge-carrying headgroup.
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Affiliation(s)
- Yufeng Wang
- Michigan State University, Department of Chemistry, East Lansing, MI 48824, USA.
| | - Laxmi Adhikari
- University of Missouri, Department of Chemistry, Columbia, MO 65211, USA
| | - Gary A Baker
- University of Missouri, Department of Chemistry, Columbia, MO 65211, USA
| | - G J Blanchard
- Michigan State University, Department of Chemistry, East Lansing, MI 48824, USA.
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13
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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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14
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Hossain MI, Blanchard GJ. The effect of dilution on induced free charge density gradients in room temperature ionic liquids. Phys Chem Chem Phys 2022; 24:3844-3853. [PMID: 35088776 DOI: 10.1039/d1cp05027c] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on changes in the magnitude and length scale of the induced free charge density gradient, ρf, in three imidazolium room temperature ionic liquids (RTILs) with dilution by methanol and acetonitrile. Using depth- and time-resolved fluorescence measurements of cresyl violet rotational diffusion, we find that ρf persists in RTILs to varying degrees depending on RTIL and diluent identity, and in all cases the functional form of ρf is not a smooth monotonic diminution in either magnitude or persistence length with increasing diluent, but a stepwise collapse. This finding is consistent with changes in the bulk RTIL as a function of dilution seen using rotational diffusion measurements that show the rotating entity in bulk RTILs exhibits a larger effective hydrodynamic volume than would be expected based on bulk viscosity data for the diluted RTILs. This excess hydrodynamic volume can be understood in the context of aggregation of RTIL ion pairs in the diluted RTIL system. The size of the aggregates is seen to depend on RTIL identity and diluent, and in all cases aggregate size increases with increasing dilution. This finding is consistent with the ρf dependence on dilution data. The collapse of ρf is seen to correlate with the onset of RTIL ion pair dimer formation, a condition that may facilitate dissociated RTIL ion mobility in the binary system.
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Affiliation(s)
- Md Iqbal Hossain
- Michigan State University, Department of Chemistry, East Lansing, MI 48824, USA.
| | - G J Blanchard
- Michigan State University, Department of Chemistry, East Lansing, MI 48824, USA.
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15
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Biswas A, Mallik BS. 2D IR spectra of the intrinsic vibrational probes of ionic liquid from dispersion corrected DFT-MD simulations. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Ma X, Zhang Y, Ma X, Zhao N, Chu X, Ma S, Liu C, Xu W. Adsorption of Acid Orange and Reactive Red by DK110 Loaded Ionic Liquid. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202100215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Xintao Ma
- School of Chemistry and Materials Science Ludong University Yantai 264025 China
| | - Yu Zhang
- School of Chemistry and Materials Science Ludong University Yantai 264025 China
| | - Xinxin Ma
- School of Chemistry and Materials Science Ludong University Yantai 264025 China
| | - Na Zhao
- School of Chemistry and Materials Science Ludong University Yantai 264025 China
| | - Xiaoxiao Chu
- School of Chemistry and Materials Science Ludong University Yantai 264025 China
| | - Songmei Ma
- School of Chemistry and Materials Science Ludong University Yantai 264025 China
| | - Chunping Liu
- School of Chemistry and Materials Science Ludong University Yantai 264025 China
| | - Wenlong Xu
- School of Chemistry and Materials Science Ludong University Yantai 264025 China
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17
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Yoshida T, Okoshi M, Kawai A. O 2 solvation cavity in voids of ionic liquids studied by the solvatochromic red shift of O 2( 1Δ g) phosphorescence. J Chem Phys 2021; 155:234503. [PMID: 34937375 DOI: 10.1063/5.0073955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Phosphorescence spectroscopy of singlet oxygen [=O2(1Δg)] was applied to study the solvation properties of small solute molecule, O2, in ionic liquids. Unlike conventional molecular solvents, the spectral red shift of the O2(1Δg) phosphorescence in ionic liquids from the gas phase was found to depend not only on the refractive index of solvents but also on the vdW volume of anions. This unusual spectral shift of the O2(1Δg) luminescence is interpreted by considering the size of solvation cavities in voids, which is estimated by analyzing the free volume in ionic liquids. These results suggest the potential of the O2(1Δg) phosphorescence spectral shift measurement in the study of molecular-scale voids in ionic liquids.
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Affiliation(s)
- Tsuyoshi Yoshida
- Department of Electrical and Electronic Engineering, National Defense Academy, 1-10-20, Hashirimizu, Yokosuka, Kanagawa 239-8686, Japan
| | - Masayuki Okoshi
- Department of Electrical and Electronic Engineering, National Defense Academy, 1-10-20, Hashirimizu, Yokosuka, Kanagawa 239-8686, Japan
| | - Akio Kawai
- Department of Chemistry, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka-shi, Kanagawa 259-1293, Japan
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18
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Wang YL, Li B, Laaksonen A. Coarse-grained simulations of ionic liquid materials: from monomeric ionic liquids to ionic liquid crystals and polymeric ionic liquids. Phys Chem Chem Phys 2021; 23:19435-19456. [PMID: 34524303 DOI: 10.1039/d1cp02662c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ionic liquid (IL) materials are promising electrolytes with striking physicochemical properties for energy and environmental applications. Heterogeneous structures and transport quantities of monomeric and polymeric ILs are intrinsically intercorrelated and span multiple spatiotemporal scales, which is more feasible for coarse-grained (CG) simulations than atomistic modelling. Herein we constructed a novel CG model for ethyl-imidazolium tetrafluoroborate ILs with varied cation alkyl chains ranging from C2 to C20, and the interaction parameters were validated against representative static and dynamic properties that were obtained from atomistic reference simulations and experimental characterizations at relevant thermodynamic states. This CG model was extended to study thermotropic phase behaviors of monomeric ILs and to explore ion association structures and ion transport quantities in polymeric ILs with different architectures. A systematic analysis of structural and dynamical quantities identifies an evolution of liquid morphology from homogeneous to nanosegregated structures and then a smectic mesomorphism via a gradual lengthening of cation alkyl chains, and thereafter a distinct structural transition characterized by a monotonic decrease in orientational and translational order parameters in a sequential heating cascade. Backbone and pendant polymeric ILs exhibit evident anion association structures with cation monomers and polymer chains, and striking intra- and interchain coordinations between cation monomers owing to an intrinsic polymer architecture effect. Such a peculiar ion pairing association leads to a progressive increase in anion intrachain hopping probabilities, and a concomitant decrease in anion interchain hopping events with a gradual lengthening of polymeric ILs. The anion diffusivities in polymeric ILs are intrinsically correlated with ion pairing association lifetimes and ion structural relaxation times via a universal power law correlation D ∼ τ-1, irrespective of polymer architectures.
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Affiliation(s)
- Yong-Lei Wang
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
| | - Bin Li
- School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Aatto Laaksonen
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden. .,State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China.,Centre of Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry, Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania.,Department of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
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19
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Bandegi A, Marquez Garcia M, Bañuelos JL, Firestone MA, Foudazi R. Soft nanoconfinement of ionic liquids in lyotropic liquid crystals. SOFT MATTER 2021; 17:8118-8129. [PMID: 34525150 DOI: 10.1039/d1sm00796c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nanoconfinement of ionic liquids (ILs) influences their physicochemical properties. In this study, we investigate the effect of soft nanoconfinement imposed by lyotropic liquid crystals (LLCs) on ILs. The LLC ion gels are obtained through self-assembly of a short chain block copolymer (BCP) of polyethylene-block-poly(ethylene oxide), PE-b-PEO, in ILs. The effect of confinement on the interaction of ions with PEO is investigated through electrochemical impedance spectroscopy (EIS) and carbon dioxide (CO2) absorption measurements. The results show that the synergistic effect on the CO2 absorption capacity of LLC ion gels takes place as a result of confinement. Formation of IL pathways through the LLC increases the CO2 solubility, absorption capacity, and absorption rate. Increasing the concentration of block copolymer in the LLC structure enhances the dissociation of ILs and consequently lowers CO2 absorption. Therefore, the competing effects of confinement and IL-PEO interaction control the properties of LLC ion gels.
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Affiliation(s)
- Alireza Bandegi
- Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, NM, 88003, USA.
| | - Maria Marquez Garcia
- Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, NM, 88003, USA.
| | - Jose L Bañuelos
- Department of Physics, The University of Texas at El Paso, El Paso, TX, 79968, USA
| | - Millicent A Firestone
- Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Materials Physics & Applications Division, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, USA
| | - Reza Foudazi
- Department of Chemical and Materials Engineering, New Mexico State University, Las Cruces, NM, 88003, USA.
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20
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Sun J, Wang Y, Liu J, Xu Q, Yin J. Highly selective separation of CO2/N2 using [Emim][Tf2N] supported ionic liquid membranes prepared by supercritical fluid deposition. J Supercrit Fluids 2021. [DOI: 10.1016/j.supflu.2020.105139] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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21
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Kelsheimer CJ, Garrett-Roe S. Intramolecular Vibrational Energy Relaxation of CO 2 in Cross-Linked Poly(ethylene glycol) Diacrylate-Based Ion Gels. J Phys Chem B 2021; 125:1402-1415. [PMID: 32955891 DOI: 10.1021/acs.jpcb.0c06685] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultrafast two-dimensional infrared spectroscopy (2D-IR) and Fourier transform infrared spectroscopy (FTIR) were used to measure carbon dioxide (CO2) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]), cross-linked low-molecular-weight poly(ethylene glycol) diacrylate (PEGDA), and an ion gel composed of a 50 vol % blend of the two. The center frequency of the antisymmetric stretch, ν3, of CO2 shifts monotonically to lower wavenumbers with increasing polymer content, with the largest line width in the ion gel (6 cm-1). Increasing polymer content slows both spectral diffusion and vibrational energy relaxation (VER) rates. An unexpected excited-state absorbance peak appears in the 2D-IR of cross-linked PEGDA due to VER from the antisymmetric stretch into the bending mode, ν2. Thirty-two response functions are necessary to describe the observed features in the 2D-IR spectra. Nonlinear least-squares fitting extracts both spectral diffusion and VER rates. In the ion gel, CO2 exhibits spectral diffusion dynamics that lie between that of the pure compounds. The kinetics of VER reflect both fast excitation and de-excitation of the bending mode, similar to the ionic liquid (IL), and slow overall vibrational population relaxation, similar to the cross-linked polymer. The IL-like and polymer-like dynamics suggest that the CO2 resides at the interface of the two components in the ion gel.
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Affiliation(s)
- C J Kelsheimer
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Sean Garrett-Roe
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
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22
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Wang Y, Swain GM, Blanchard GJ. Charge-Induced Birefringence in a Room-Temperature Ionic Liquid. J Phys Chem B 2021; 125:950-955. [PMID: 33464907 DOI: 10.1021/acs.jpcb.0c10045] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have reported previously on the existence of a surface charge-induced free charge density gradient (ρf) in room-temperature ionic liquids (RTILs) with a characteristic persistence length of ca. 50 μm [Ma, K. Langmuir 2016, 32, 9507-9512]. The free charge density gradient is related to the dielectric response of the RTIL. We report here on the existence of a surface charge-induced gradient in the RTIL refractive index and quantify the relationship between the index gradient and ρf. Because ρf is uniaxial, the induced refractive index gradient is manifested as an induced birefringence. The RTIL sample holder has a curved surface such that the RTIL can function as a lens, and ρf is controlled by the surface charge density (σs) of the (concave) RTIL support. Current passed through an indium-doped tin oxide (ITO) surface layer on the support surface controls σs. The far-field image of light passed through the RTIL lens as a function of σs is used to measure the charge-induced changes of n in the RTIL. We demonstrate a modulation of the refractive index on the order of 15%, proportional to σs. This report places the relationship between ρf and RTIL dielectric response on a quantitative footing and suggests the utility of RTILs for electro-optic applications.
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Affiliation(s)
- Yufeng Wang
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - Greg M Swain
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824-1322, United States
| | - G J Blanchard
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824-1322, United States
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23
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Wang Y, Parvis F, Hossain MI, Ma K, Jarošová R, Swain GM, Blanchard GJ. Local and Long-Range Organization in Room Temperature Ionic Liquids. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:605-615. [PMID: 33411540 DOI: 10.1021/acs.langmuir.9b03995] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Room temperature ionic liquids (RTILs) have a wide range of current and potential applications, in areas ranging from supercapacitor energy storage to sequestration of toxic gas phase species and use as reusable solvents for selected organic reactions. All these applications stem from their unique physical and chemical properties, which remain understood to only a limited extent. Among the issues of greatest importance is the extent to which RTILs exist as dissociated ionic species and the length scales over which some types of organizations are seen to exist in them. In this Invited Feature Article, we review the current understanding of organization in this family of materials, where opportunities lie in terms of deepening our understanding, and what potential applications would benefit from gaining such knowledge.
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Affiliation(s)
- Yufeng Wang
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Fatemeh Parvis
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Md Iqbal Hossain
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Ke Ma
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Romana Jarošová
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Greg M Swain
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Gary J Blanchard
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
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24
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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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25
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Wang YL. Effects of Nitridation and Vinylation of Imidazolium Rings on Hydrogen Bonding Interactions, π–π-Stacking Structures, and Dynamical Heterogeneities in Imidazolium and Triazolium Ionic Liquids. J Phys Chem B 2020; 124:7452-7466. [DOI: 10.1021/acs.jpcb.0c05635] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yong-Lei Wang
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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26
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Shao Y, Wang Y, Li X, Kheirabad AK, Zhao Q, Yuan J, Wang H. Crosslinking of a Single Poly(ionic liquid) by Water into Porous Supramolecular Membranes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202002679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yue Shao
- Key Laboratory of Functional Polymer Materials of the Ministry of Education Institute of Polymer Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
| | - Yong‐Lei Wang
- Department of Materials and Environmental Chemistry Stockholm University 10691 Stockholm Sweden
| | - Xiangshuai Li
- Key Laboratory of Functional Polymer Materials of the Ministry of Education Institute of Polymer Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
| | | | - Qiang Zhao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education) School of Chemistry and Chemical Engineering Huazhong University of Science and Technology Luoyu Road No. 1037 Wuhan 430074 China
| | - Jiayin Yuan
- Department of Materials and Environmental Chemistry Stockholm University 10691 Stockholm Sweden
| | - Hong Wang
- Key Laboratory of Functional Polymer Materials of the Ministry of Education Institute of Polymer Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
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27
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Shao Y, Wang Y, Li X, Kheirabad AK, Zhao Q, Yuan J, Wang H. Crosslinking of a Single Poly(ionic liquid) by Water into Porous Supramolecular Membranes. Angew Chem Int Ed Engl 2020; 59:17187-17191. [PMID: 32583932 DOI: 10.1002/anie.202002679] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/07/2020] [Indexed: 11/06/2022]
Affiliation(s)
- Yue Shao
- Key Laboratory of Functional Polymer Materials of the Ministry of Education Institute of Polymer Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
| | - Yong‐Lei Wang
- Department of Materials and Environmental Chemistry Stockholm University 10691 Stockholm Sweden
| | - Xiangshuai Li
- Key Laboratory of Functional Polymer Materials of the Ministry of Education Institute of Polymer Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
| | | | - Qiang Zhao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage (Ministry of Education) School of Chemistry and Chemical Engineering Huazhong University of Science and Technology Luoyu Road No. 1037 Wuhan 430074 China
| | - Jiayin Yuan
- Department of Materials and Environmental Chemistry Stockholm University 10691 Stockholm Sweden
| | - Hong Wang
- Key Laboratory of Functional Polymer Materials of the Ministry of Education Institute of Polymer Chemistry College of Chemistry Nankai University Tianjin 300071 P. R. China
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28
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Wang YL, Li B, Sarman S, Mocci F, Lu ZY, Yuan J, Laaksonen A, Fayer MD. Microstructural and Dynamical Heterogeneities in Ionic Liquids. Chem Rev 2020; 120:5798-5877. [PMID: 32292036 PMCID: PMC7349628 DOI: 10.1021/acs.chemrev.9b00693] [Citation(s) in RCA: 192] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Ionic liquids (ILs) are a special category of molten salts solely composed of ions with varied molecular symmetry and charge delocalization. The versatility in combining varied cation-anion moieties and in functionalizing ions with different atoms and molecular groups contributes to their peculiar interactions ranging from weak isotropic associations to strong, specific, and anisotropic forces. A delicate interplay among intra- and intermolecular interactions facilitates the formation of heterogeneous microstructures and liquid morphologies, which further contributes to their striking dynamical properties. Microstructural and dynamical heterogeneities of ILs lead to their multifaceted properties described by an inherent designer feature, which makes ILs important candidates for novel solvents, electrolytes, and functional materials in academia and industrial applications. Due to a massive number of combinations of ion pairs with ion species having distinct molecular structures and IL mixtures containing varied molecular solvents, a comprehensive understanding of their hierarchical structural and dynamical quantities is of great significance for a rational selection of ILs with appropriate properties and thereafter advancing their macroscopic functionalities in applications. In this review, we comprehensively trace recent advances in understanding delicate interplay of strong and weak interactions that underpin their complex phase behaviors with a particular emphasis on understanding heterogeneous microstructures and dynamics of ILs in bulk liquids, in mixtures with cosolvents, and in interfacial regions.
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Affiliation(s)
- Yong-Lei Wang
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Bin Li
- School
of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, P. R. China
| | - Sten Sarman
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Francesca Mocci
- Department
of Chemical and Geological Sciences, University
of Cagliari, I-09042 Monserrato, Italy
| | - Zhong-Yuan Lu
- State
Key Laboratory of Supramolecular Structure and Materials, Institute
of Theoretical Chemistry, Jilin University, Changchun 130021, P. R. China
| | - Jiayin Yuan
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Aatto Laaksonen
- Department
of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
- State
Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
- Centre of
Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487 Iasi, Romania
- Department
of Engineering Sciences and Mathematics, Division of Energy Science, Luleå University of Technology, SE-97187 Luleå, Sweden
| | - Michael D. Fayer
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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29
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Wang YL, Li B, Laaksonen A, Yuan J. The Effect of Phenyl Substitutions on Microstructures and Dynamics of Tetraalkylphosphonium Bis(trifluoro- methylsulfonyl)imide Ionic Liquids. Chemphyschem 2020; 21:1202-1214. [PMID: 32181955 DOI: 10.1002/cphc.201901206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 02/24/2020] [Indexed: 01/15/2023]
Abstract
Extensive atomistic simulations demonstrated that a gradual substitution of hexyl chains with phenyl groups in tetraalkylphosphonium cations results in remarkable changes in hydrogen bonding interactions, liquid structures and scattering structural functions, and rotational dynamics of hexyl chains and phenyl groups in tetraalkylphosphonium bis(trifluoromethylsulfonyl)imide ionic liquids. Hydrogen donor sites in hexyl chains present competitive characteristics with those in phenyl groups in coordinating anions, as well as their continuous and intermittent hydrogen bonding dynamics. Cation-cation and anion-anion spatial correlations show concomitant shift to short distances with decreased peak intensities with variations of cation structures, whereas cation-anion correlations have a distinct shift to large radial distances due to decreased associations of anions with neighboring cations. These microstructural changes are qualitatively manifested in shifts of prominent peaks for prevalent charge alternations and adjacency correlations between ion species in scattering structural functions. Meanwhile, rotational dynamics of hexyl chains speed up, which, in turn, slow down rotations of phenyl groups, whereas anions exhibit imperceptible changes in their rotational dynamics. These computational results are intrinsically correlated with conformational flexibilities, molecular sizes, and steric hindrance effects of phenyl groups in comparison with hexyl chains, and constrained distributions of anions around cations in heterogeneous ionic environments.
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Affiliation(s)
- Yong-Lei Wang
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
| | - Bin Li
- School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai, 519082, P. R. China
| | - Aatto Laaksonen
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden.,Centre of Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry Aleea Grigore Ghica-Voda, 41A, 700487, Iasi, Romania
| | - Jiayin Yuan
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91, Stockholm, Sweden
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30
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Wu B, Breen JP, Xing X, Fayer MD. Controlling the Dynamics of Ionic Liquid Thin Films via Multilayer Surface Functionalization. J Am Chem Soc 2020; 142:9482-9492. [PMID: 32349470 DOI: 10.1021/jacs.0c03044] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The structural dynamics of planar thin films of an ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BmimNTf2) as a function of surface charge density and thickness were investigated using two-dimensional infrared (2D IR) spectroscopy. The films were made by spin coating a methanol solution of the IL on silica substrates that were functionalized with alkyl chains containing head groups that mimic the IL cation. The thicknesses of the ionic liquid films ranged from ∼50 to ∼250 nm. The dynamics of the films are slower than those in the bulk IL, becoming increasingly slow as the films become thinner. Control of the dynamics of the IL films can be achieved by adjusting the charge density on substrates through multilayer network surface functionalization. The charge density of the surface (number of positively charged groups in the network bound to the surface per unit area) is controlled by the duration of the functionalization reaction. As the charge density is increased, the IL dynamics become slower. For comparison, the surface was functionalized with three different neutral groups. Dynamics of the IL films on the functionalized neutral surfaces are faster than on any of the ionic surfaces but still slower than the bulk IL, even for the thickest films. These results can have implications in applications that employ ILs that have electrodes, such as batteries, as the electrode surface charge density will influence properties like diffusion close to the surface.
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Affiliation(s)
- Boning Wu
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - John P Breen
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Xiangyu Xing
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Michael D Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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31
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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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32
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Thomaz JE, Kramer PL, Fica-Contreras SM, Hoffman DJ, Fayer MD. Reorientation-induced Stokes shifts caused by directional interactions in electronic spectroscopy: Fast dynamics of poly(methyl methacrylate). J Chem Phys 2019; 150:194201. [PMID: 31117782 DOI: 10.1063/1.5094806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Dynamic Stokes shift measurements report on structural relaxation, driven by a dipole created in a chromophore by its excitation from the ground electronic state to the S1 state. Here, we demonstrate that it is also possible to have an additional contribution from orientational relaxation of the Stokes shift chromophore. This effect, called reorientation-induced Stokes shift (RISS), can be observed when the reorientation of the chromophore and the solvent structural relaxation occur on similar time scales. Through a vector interaction, the electronic transition of the chromophore couples to its environment. The orientational diffusive motions of the chromophores will have a slight bias toward reducing the transition energy (red shift) as do the solvent structural diffusive motions. RISS is manifested in the polarization-dependence of the fluorescence Stokes shift using coumarin 153 (C153) in poly(methyl methacrylate) (PMMA). A similar phenomenon, reorientation-induced spectral diffusion (RISD), has been observed and theoretically explicated in the context of two dimensional infrared (2D IR) experiments. Here, we generalize the existing RISD theory to include properties of electronic transitions that generally are not present in vibrational transitions. Expressions are derived that permit determination of the structural dynamics by accounting for the RISS contributions. Using these generalized equations, the structural dynamics of the medium can be measured for any system in which the directional interaction is well represented by a first order Stark effect and RISS or RISD is observed. The theoretical results are applied to the PMMA data, and the structural dynamics are obtained and discussed.
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Affiliation(s)
- Joseph E Thomaz
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Patrick L Kramer
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | | | - David J Hoffman
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Michael D Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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33
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Gera R, Meloni SL, Anna JM. Unraveling Confined Dynamics of Guests Trapped in Self-Assembled Pd 6L 4 Nanocages by Ultrafast Mid-IR Polarization-Dependent Spectroscopy. J Phys Chem Lett 2019; 10:413-418. [PMID: 30630311 PMCID: PMC6536308 DOI: 10.1021/acs.jpclett.8b03485] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Self-assembled coordination cages form host-guest complexes through weak noncovalent interactions. Knowledge of how these weak interactions affect the structure, reactivity, and dynamics of guest molecules is important to further the design principles of current systems and optimize their specific functions. We apply ultrafast mid-IR polarization-dependent pump-probe spectroscopy to probe the effects of two Pd6L4 self-assembled nanocages on the properties and dynamics of fluxional group-VIII metal carbonyl guest molecules. We find that the interactions between the Pd6L4 nanocages and guest molecules act to alter the ultrafast dynamics of the guests, restricting rotational diffusional motion and decreasing the vibrational lifetime.
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Affiliation(s)
| | | | - Jessica M. Anna
- Corresponding Author: To whom correspondence should be addressed:
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34
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Rea R, Angelis MGD, Baschetti MG. Models for Facilitated Transport Membranes: A Review. MEMBRANES 2019; 9:E26. [PMID: 30717381 PMCID: PMC6409752 DOI: 10.3390/membranes9020026] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 11/16/2022]
Abstract
Facilitated transport membranes are particularly promising in different separations, as they are potentially able to overcome the trade-off behavior usually encountered in solution-diffusion membranes. The reaction activated transport is a process in which several mechanisms take place simultaneously, and requires a rigorous theoretical analysis, which unfortunately is often neglected in current studies more focused on material development. In this work, we selected and reviewed the main mathematical models introduced to describe mobile and fixed facilitated transport systems in steady state conditions, in order to provide the reader with an overview of the existing mathematical tools. An analytical solution to the mass transport problem cannot be achieved, even when considering simple reaction schemes such as that between oxygen (solute) and hemoglobin (carrier) (A+C⇄AC), that was thoroughly studied by the first works dealing with this type of biological facilitated transport. Therefore, modeling studies provided approximate analytical solutions and comparison against experimental observations and exact numerical calculations. The derivation, the main assumptions, and approximations of such modeling approaches is briefly presented to assess their applicability, precision, and flexibility in describing and understanding mobile and fixed site carriers facilitated transport membranes. The goal is to establish which mathematical tools are more suitable to support and guide the development and design of new facilitated transport systems and materials. Among the models presented, in particular, those from Teramoto and from Morales-Cabrera et al. seem the more flexible and general ones for the mobile carrier case, while the formalization made by Noble and coauthors appears the most complete in the case of fixed site carrier membranes.
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Affiliation(s)
- Riccardo Rea
- Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali (DICAM), Università di Bologna, Via Terracini 28, 40131 Bologna, Italy.
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Abedini A, Crabtree E, Bara JE, Turner CH. Molecular analysis of selective gas adsorption within composites of ionic polyimides and ionic liquids as gas separation membranes. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2018.08.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Nishida J, Breen JP, Wu B, Fayer MD. Extraordinary Slowing of Structural Dynamics in Thin Films of a Room Temperature Ionic Liquid. ACS CENTRAL SCIENCE 2018; 4:1065-1073. [PMID: 30159404 PMCID: PMC6107873 DOI: 10.1021/acscentsci.8b00353] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Indexed: 05/03/2023]
Abstract
The role that interfaces play in the dynamics of liquids is a fundamental scientific problem with vast importance in technological applications. From material science to biology, e.g., batteries to cell membranes, liquid properties at interfaces are frequently determinant in the nature of chemical processes. For most liquids, like water, the influence of an interface falls off on a ∼1 nm distance scale. Room temperature ionic liquids (RTILs) are a vast class of unusual liquids composed of complex cations and anions that are liquid salts at room temperature. They are unusual liquids with properties that can be finely tuned by selecting the structure of the cation and anion. RTILs are being used or developed in applications such as batteries, CO2 capture, and liquids for biological processes. Here, it is demonstrated quantitatively that the influence of an interface on RTIL properties is profoundly different from that observed in other classes of liquids. The dynamics of planar thin films of the room temperature ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BmimNTf2), were investigated using two-dimensional infrared spectroscopy (2D IR) with the CN stretch of SeCN- as the vibrational probe. The structural dynamics (spectral diffusion) of the thin films with controlled nanometer thicknesses were measured and compared to the dynamics of the bulk liquid. The samples were prepared by spin coating the RTIL, together with the vibrational probe, onto a surface functionalized with an ionic monolayer that mimics the structure of the BmimNTf2. Near-Brewster's angle reflection pump-probe geometry 2D IR facilitated the detection of the exceedingly small signals from the films, some of which were only 14 nm thick. Even in quarter micron (250 nm) thick films, the observed dynamics were much slower than those of the bulk liquid. Using a new theoretical description, the correlation length (exponential falloff of the influence of the interfaces) was found to be 28 ± 5 nm. This very long correlation length, ∼30 times greater than that of water, has major implications for the use of RTILs in devices and other applications.
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Wang YL. Competitive Microstructures Versus Cooperative Dynamics of Hydrogen Bonding and π-Type Stacking Interactions in Imidazolium Bis(oxalato)borate Ionic Liquids. J Phys Chem B 2018; 122:6570-6585. [DOI: 10.1021/acs.jpcb.8b02899] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yong-Lei Wang
- Department of Chemistry, Stanford University,
Stanford, California 94305, United States
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He X, Xu F, Yu P, Wu Y, Wang F, Zhao Y, Wang J. Solvent-dependent structural dynamics of an azido-platinum complex revealed by linear and nonlinear infrared spectroscopy. Phys Chem Chem Phys 2018; 20:9984-9996. [PMID: 29619447 DOI: 10.1039/c7cp08606g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The vibrational and anisotropic relaxation dynamics and structural dynamics of a potential anticancer prodrug, trans,trans,trans-[Pt(N3)2(OH)2(py)2], were investigated using time-resolved infrared pump-probe spectroscopy and ultrafast two-dimensional infrared (2D IR) spectroscopy. Herein, two representative bio-friendly solvents, H2O and DMSO, were used, in which the local structural and dynamical variations were monitored using the antisymmetric linear combination of the two N3 stretching vibrational modes as an infrared probe. It was found that the vibrational relaxation process of the N3 antisymmetric stretching (as) mode in H2O is two to three times faster than that in DMSO. The anisotropic relaxation process of the anticancer prodrug was observed to be hindered in DMSO; this indicated a tighter solvent environment around the sample molecule in this solvent. The vibrational frequency time correlation of the N3 antisymmetric stretching mode in H2O decays with a time constant of 1.94 ps, in agreement with the hydrogen bond formation and breaking times of water. In DMSO, the frequency time correlation of the N3 as mode decays on a much longer time scale; this further indicates its sensitivity to the out-layer DMSO structural dynamics, which are relatively static in the experimental time window.
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Affiliation(s)
- Xuemei He
- Beijing National Laboratory for Molecular Sciences, Molecular Reaction Dynamics Laboratory, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
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Shin JY, Yamada SA, Fayer MD. Influence of Water on Carbon Dioxide and Room Temperature Ionic Liquid Dynamics: Supported Ionic Liquid Membrane vs the Bulk Liquid. J Phys Chem B 2018; 122:2389-2395. [DOI: 10.1021/acs.jpcb.8b01163] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jae Yoon Shin
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven A. Yamada
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Michael D. Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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40
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Ramesh P, Loring RF. Thermal Population Fluctuations in Two-Dimensional Infrared Spectroscopy Captured with Semiclassical Mechanics. J Phys Chem B 2018; 122:3647-3654. [DOI: 10.1021/acs.jpcb.7b12122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Prashanth Ramesh
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Roger F. Loring
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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Thomaz JE, Bailey HE, Fayer MD. The influence of mesoscopic confinement on the dynamics of imidazolium-based room temperature ionic liquids in polyether sulfone membranes. J Chem Phys 2017; 147:194502. [DOI: 10.1063/1.5003036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Joseph E. Thomaz
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Heather E. Bailey
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Michael D. Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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