1
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Butcher RJ, Purdy AP. 2-Ethyl-4-methyl-1 H-imidazol-3-ium bromide. IUCRDATA 2022; 7:x221172. [PMID: 36628188 PMCID: PMC9815129 DOI: 10.1107/s2414314622011725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 12/06/2022] [Indexed: 12/23/2022] Open
Abstract
In the title mol-ecular salt, C6H11N2 +·Br-, the components are linked by N-H⋯Br⋯H-N hydrogen bonds into C(8)chains of alternating cations and anions propagating in the b-axis direction; these chains are cross-linked in the c-axis direction by weak C-H⋯Br hydrogen bonds.
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Affiliation(s)
- Ray J. Butcher
- Department of Chemistry, Howard University, 525 College Street NW, Washington DC 20059, USA
| | - Andrew P. Purdy
- Chemistry Division, Code 6123, Naval Research Laboratory, 4555 Overlook Av, SW, Washington DC 20375-5342, USA
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2
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Tikhonov DS, Scutelnic V, Sharapa DI, Krotova AA, Dmitrieva AV, Obenchain DA, Schnell M. Structures of the (Imidazole)nH+ ... Ar (n=1,2,3) complexes determined from IR spectroscopy and quantum chemical calculations. Struct Chem 2022. [DOI: 10.1007/s11224-022-02053-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AbstractHere, we present new cryogenic infrared spectra of the (Imidazole)$$_{n}\mathrm{H}^{+}$$
n
H
+
(n=1,2,3) ions. The data was obtained using helium tagging infrared predissociation spectroscopy. The new results were compared with the data obtained by Gerardi et al. (Chem. Phys. Lett. 501:172–178, 2011) using the same technique but with argon as a tag. Comparison of the two experiments, assisted by theoretical calculations, allowed us to evaluate the preferable attachment positions of argon to the (Imidazole)$$_{n}\mathrm{H}^{+}$$
n
H
+
frame. Argon attaches to nitrogen-bonded hydrogen in the case of the (Imidazole)H$$^+$$
+
ion, while in (Imidazole)$$_{2}\mathrm{H}^{+}$$
2
H
+
and (Imidazole)$$_{3}\mathrm{H}^{+}$$
3
H
+
the preferred docking sites for the argon are in the center of the complex. This conclusion is supported by analyzing the spectral features attributed to the N–H stretching vibrations. Symmetry adapted perturbation theory (SAPT) analysis of the non-covalent forces between argon and the (Imidazole)$$_{n}\mathrm{H}^{+}$$
n
H
+
(n=1,2,3) frame revealed that this switch of docking preference with increasing complex size is caused by an interplay between induction and dispersion interactions.
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3
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Tadokoro M, Itoh M, Nishimura R, Sekiguchi K, Hoshino N, Kamebuchi H, Miyazaki J, Kobayashi F, Mizuno M, Akutagawa T. Proton Conduction at High Temperature in High-Symmetry Hydrogen-Bonded Molecular Crystals of Ru III Complexes with Six Imidazole-Imidazolate Ligands. Chemistry 2022; 28:e202201397. [PMID: 35760750 PMCID: PMC9545294 DOI: 10.1002/chem.202201397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Indexed: 11/06/2022]
Abstract
A new H-bonded crystal [RuIII (Him)3 (Im)3 ] with three imidazole (Him) and three imidazolate (Im- ) groups was prepared to obtain a higher-temperature proton conductor than a Nafion membrane with water driving. The crystal is constructed by complementary N-H⋅⋅⋅N H-bonds between the RuIII complexes and has a rare Icy-c* cubic network topology with a twofold interpenetration without crystal anisotropy. The crystals show a proton conductivity of 3.08×10-5 S cm-1 at 450 K and a faster conductivity than those formed by only HIms. The high proton conductivity is attributed to not only molecular rotations and hopping motions of HIm frameworks that are activated at ∼113 K, but also isotropic whole-molecule rotation of [RuIII (Him)3 (Im)3 ] at temperatures greater than 420 K. The latter rotation was confirmed by solid-state 2 H NMR spectroscopy; probable proton conduction routes were predicted and theoretically considered.
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Affiliation(s)
- Makoto Tadokoro
- Department of ChemistryFaculty of ScienceTokyo University of ScienceKagurazaka 1–3Shinjuku-kuTokyo162-8601Japan
| | - Masaki Itoh
- Department of ChemistryFaculty of ScienceTokyo University of ScienceKagurazaka 1–3Shinjuku-kuTokyo162-8601Japan
| | - Ryota Nishimura
- Department of ChemistryFaculty of ScienceTokyo University of ScienceKagurazaka 1–3Shinjuku-kuTokyo162-8601Japan
| | - Kensuke Sekiguchi
- Department of ChemistryFaculty of ScienceTokyo University of ScienceKagurazaka 1–3Shinjuku-kuTokyo162-8601Japan
| | - Norihisa Hoshino
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM)Tohoku UniversityKatahira, 2–1-1, Aoba-kuSendai980-8577Japan
| | - Hajime Kamebuchi
- Department of ChemistryCollege of Humanities and SciencesNihon UniversitySakurajyosui 3–25-40Setagaya-kuTokyo156-8550Japan
| | - Jun Miyazaki
- Department of Natural SciencesSchool of EngineeringTokyo Denki UniversitySenjuasahi-cho 5Adachi-kuTokyo120-8551Japan
| | - Fumiya Kobayashi
- Department of ChemistryFaculty of ScienceTokyo University of ScienceKagurazaka 1–3Shinjuku-kuTokyo162-8601Japan
| | - Motohiro Mizuno
- Graduate School of Natural Science and TechnologyKanazawa UniversityKanazawa920-1192Japan
| | - Tomoyuki Akutagawa
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM)Tohoku UniversityKatahira, 2–1-1, Aoba-kuSendai980-8577Japan
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4
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Kostin MA, Pylaeva S, Tolstoy P. Phosphine oxides as NMR and IR spectroscopic probes for geometry and energy of PO···H–A hydrogen bonds. Phys Chem Chem Phys 2022; 24:7121-7133. [DOI: 10.1039/d1cp05939d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work we evaluate the possibility to use the NMR and IR spectral properties of P=O group to estimate the geometry and strength of hydrogen bonds which it forms...
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5
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Hori Y, Dekura S, Sunairi Y, Ida T, Mizuno M, Mori H, Shigeta Y. Proton Conduction Mechanism for Anhydrous Imidazolium Hydrogen Succinate Based on Local Structures and Molecular Dynamics. J Phys Chem Lett 2021; 12:5390-5394. [PMID: 34080418 DOI: 10.1021/acs.jpclett.1c01280] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Anhydrous organic crystalline materials incorporating imidazolium hydrogen succinate (Im-Suc), which exhibit high proton conduction even at temperatures above 100 °C, are attractive for elucidating proton conduction mechanisms toward the development of solid electrolytes for fuel cells. Herein, quantum chemical calculations were used to investigate the proton conduction mechanism in terms of hydrogen-bonding (H-bonding) changes and restricted molecular rotation in Im-Suc. The local H-bond structures for proton conduction were characterized by vibrational frequency analysis and compared with corresponding experimental data. The calculated potential energy surface involving proton transfer (PT) and imidazole (Im) rotational motion showed that PT between Im and succinic acid was a rate-limiting step for proton transport in Im-Suc and that proton conduction proceeded via the successive coupling of PT and Im rotational motion based on a Grotthuss-type mechanism. These findings provide molecular-level insights into proton conduction mechanisms for Im-based (or -incorporated) H-bonding organic proton conductors.
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Affiliation(s)
- Yuta Hori
- Center for Computational Sciences, University of Tsukuba, Tsukuba 305-8577, Japan
| | - Shun Dekura
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Yoshiya Sunairi
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Tomonori Ida
- Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan
| | - Motohiro Mizuno
- Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan
- NanoMaterials Research Institute, Kanazawa University, Kanazawa 920-1192, Japan
| | - Hatsumi Mori
- The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Yasuteru Shigeta
- Center for Computational Sciences, University of Tsukuba, Tsukuba 305-8577, Japan
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6
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Zhu Z, Luo X, Sokolov AP, Paddison SJ. Proton Transfer in Phosphoric Acid-Based Protic Ionic Liquids: Effects of the Base. J Phys Chem A 2020; 124:4141-4149. [PMID: 32314922 DOI: 10.1021/acs.jpca.0c02863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electronic structure calculations were performed to understand highly decoupled conductivities recently reported in protic ionic liquids (PILs). To develop a molecular-level understanding of the mechanisms of proton conductivity in PILs, minimum-energy structures of trimethylamine, imidazole, lidocaine, and creatinine (CRT) with the addition of one to three phosphoric acid (PA) molecules were determined at the B3LYP/6-311G** level of theory with the inclusion of an implicit solvation model (SMD with ε = 61). The proton affinity of the bases and zero-point energy corrected binding energies were computed at a similar level of theory. Proton dissociation from PA occurs in all systems, resulting in the formation of ion pairs due to the relatively strong basicity of the bases (proton acceptors) and the effect of the high dielectric constant solvent in stabilizing the charge separation. The second and third PA molecules preferentially form "ring-like" hydrogen bonds with one another instead of forming hydrogen bonds at the donor and acceptor sites of the bases. Potential energy scans reveal that the bases with stronger proton affinity exert greater influence on the energetics of proton transfer between the individual PA molecules. However, the effects are minimal when shifted into a single-well from a double-well potential. Barrierless proton transfer was observed to occur in the CRT system with several PA molecules present, implying that the CRT may be a promising PA-based PIL.
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Affiliation(s)
- Zhenghao Zhu
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Xubo Luo
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Alexei P Sokolov
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Stephen J Paddison
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
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7
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Li A, Yan T. Proton Propensity and Orientation of Imidazolium Cation at Liquid Imidazole-Vacuum Interface: A Molecular Dynamics Simulation. J Phys Chem B 2020; 124:4010-4016. [PMID: 32309950 DOI: 10.1021/acs.jpcb.9b11918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Imidazole has gained attention as an alternative to anhydrous proton conductor in high-temperature proton exchange membrane fuel cells. A detailed investigation of proton propensity and the orientation of the imidazolium cation at the liquid-vacuum interface is important for understanding the interfacial properties of imidazole-based proton-conductive materials. Here, we perform all-atom molecular dynamics simulation on a slab model of the liquid imidazole-vacuum interface. Proton transportation process between the imidazolium cation and neutral imidazole molecules is described by the multistate empirical valence bond model of imidazole developed previously. The imidazolium cation shows a tendency to stay in the bulk region rather than at the outermost surface, and the NN vectors and norm vectors of both the imidazolium cation and imidazole molecules are more probable to be perpendicular to the surface normal vector at the interface than in the bulk. The orientation of the hydrogen bond cluster shows the same tendency as the NN vectors, which indicates that proton transportation along the direction of the surface normal vector is hindered. The instantaneous surface analyses show that the fluctuation is depressed when the imidazolium cation is near the outermost surface, which makes it less favorable for the cation appearing at the interface.
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Affiliation(s)
- Ailin Li
- Institute of New Energy Chemistry, School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University, Tianjin 300350, China.,College of Science, Civil Aviation University of China, Tianjin 300300, China
| | - Tianying Yan
- Institute of New Energy Chemistry, School of Materials Science and Engineering, National Institute for Advanced Materials, Nankai University, Tianjin 300350, China
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8
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Fadeeva Y, Gruzdev M, Kudryakova N, Shmukler L, Safonova L. Physico-chemical characterization of alkyl-imidazolium protic ionic liquids. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.111305] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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9
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Tritt-Goc J, Lindner Ł, Bielejewski M, Markiewicz E, Pankiewicz R. Proton conductivity and proton dynamics in nanocrystalline cellulose functionalized with imidazole. Carbohydr Polym 2019; 225:115196. [PMID: 31521266 DOI: 10.1016/j.carbpol.2019.115196] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 08/09/2019] [Accepted: 08/12/2019] [Indexed: 11/25/2022]
Abstract
In the present study, we report the synthesis, electrical and dynamic properties of a new generation bio-based nanocomposite, that is a proton-exchange membrane based on nanocrystalline cellulose (CNC) and imidazole (Im). CNC serves as supporting material and imidazole acts as a proton donor and proton acceptor at the same time. The nanocomposite (1.3 CNC-Im) was synthesized as a film and shows proton conductivity equal to 4.0 × 10-1 S/m at 160 °C in anhydrous conditions. Analysis of impedance measurements and NMR spectra provided some insight into the macroscopic and microscopic processes involved in proton transport in 1.3 CNC-Im. Local processes such as reorientation of imidazole rings and breaking of hydrogen bonds are identified and their activation energies are calculated. The energies of the macroscopic and microscopic proton transport in CNC-Im film are correlated. The percolation model used confirmed the percolation nature of conductivity in cellulose composites with imidazole.
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Affiliation(s)
- J Tritt-Goc
- Institute of Molecular Physics Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland.
| | - Ł Lindner
- Institute of Molecular Physics Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland.
| | - M Bielejewski
- Institute of Molecular Physics Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland.
| | - E Markiewicz
- Institute of Molecular Physics Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland.
| | - R Pankiewicz
- Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.
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10
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Mora Cardozo JF, Embs JP, Benedetto A, Ballone P. Equilibrium Structure, Hydrogen Bonding, and Proton Conductivity in Half-Neutralized Diamine Ionic Liquids. J Phys Chem B 2019; 123:5608-5625. [PMID: 30875220 DOI: 10.1021/acs.jpcb.9b00890] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent experiments on proton conducting ionic liquids point to half-neutralized diamine-triflate salts as promising candidates for applications in power generation and energy conversion electrochemical devices. Structural and dynamical properties of the simplest among these compounds are investigated by a combination of density functional theory (DFT) and molecular dynamics (MD) simulations based on an empirical force field. Three different cations have been considered, consisting of a pair of amine-ammonium terminations joined by a short aliphatic segment -(CH2) n- with n = 2, 3, and 4. First, the ground state structure, vibrational eigenstates, and hydrogen-bonding properties of single ions, neutral ion pairs, small neutral aggregates of up to eight ions, and molecularly thin hydrogen bonded wires have been investigated by DFT computations. Second, structural and dynamical properties of homogeneous liquid and amorphous phases are investigated by MD simulations over the temperature range of 200 ≤ T ≤ 440 K. Structure factors, radial distribution functions, diffusion coefficient, and electrical conductivity are computed and discussed, highlighting the inherent structural heterogeneity of these compounds. The core investigation, however, is the characterization of connected paths consisting of cation chains that could support proton transport via a Grotthuss-type mechanism. Since simulations are carried out using a force field of fixed bonding topology, this analysis is based on the equilibrium structure only, using geometrical criteria to identify potential paths for proton conduction. Paths of connected cations can reach a length of 80 cations and 30 Å, provided that bridging oxygen atoms from triflate anions are taken into account. The effects of water contamination at 1% weight concentration on the structure, dynamics, and paths for proton transport are discussed.
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Affiliation(s)
- Juan F Mora Cardozo
- Laboratory for Neutron Scattering and Imaging , Paul Scherrer Institute , Villigen PSI, Villigen 5232 , Switzerland
| | - J P Embs
- Laboratory for Neutron Scattering and Imaging , Paul Scherrer Institute , Villigen PSI, Villigen 5232 , Switzerland
| | - A Benedetto
- Laboratory for Neutron Scattering and Imaging , Paul Scherrer Institute , Villigen PSI, Villigen 5232 , Switzerland.,Department of Sciences , University of Roma Tre , Via della Vasca Navale 84 , 00146 Rome , Italy
| | - P Ballone
- Italian Institute of Technology , Via Morego 30 , 16163 Genova , Italy
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11
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Shin JY, Wang YL, Yamada SA, Hung ST, Fayer MD. Imidazole and 1-Methylimidazole Hydrogen Bonding and Nonhydrogen Bonding Liquid Dynamics: Ultrafast IR Experiments. J Phys Chem B 2019; 123:2094-2105. [DOI: 10.1021/acs.jpcb.8b11299] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jae Yoon Shin
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Yong-Lei Wang
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven A. Yamada
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Samantha T. Hung
- 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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12
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Vu QT, Yamada H, Yogo K. Exploring the Role of Imidazoles in Amine-Impregnated Mesoporous Silica for CO2 Capture. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.7b04722] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Quyen T. Vu
- Graduate
School of Material Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma,
Nara 630-0192, Japan
| | - Hidetaka Yamada
- Graduate
School of Material Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma,
Nara 630-0192, Japan
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan
| | - Katsunori Yogo
- Graduate
School of Material Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama-cho, Ikoma,
Nara 630-0192, Japan
- Research Institute of Innovative Technology for the Earth (RITE), 9-2 Kizugawadai, Kizugawa, Kyoto 619-0292, Japan
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13
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Hori Y, Chikai T, Ida T, Mizuno M. Local structure and hydrogen bond characteristics of imidazole molecules for proton conduction in acid and base proton-conducting composite materials. Phys Chem Chem Phys 2018; 20:10311-10318. [DOI: 10.1039/c7cp08396c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protons in composite materials of acidic polymers and imidazole molecules transport with rotational motion of imidazole in hydrogen bonds.
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Affiliation(s)
- Yuta Hori
- Chemistry Course, Division of Material Chemistry
- Graduate School of Natural Science and Technology
- Kanazawa University
- Kanazawa 920-1192
- Japan
| | - Takuma Chikai
- Chemistry Course, Division of Material Chemistry
- Graduate School of Natural Science and Technology
- Kanazawa University
- Kanazawa 920-1192
- Japan
| | - Tomonori Ida
- Chemistry Course, Division of Material Chemistry
- Graduate School of Natural Science and Technology
- Kanazawa University
- Kanazawa 920-1192
- Japan
| | - Motohiro Mizuno
- Chemistry Course, Division of Material Chemistry
- Graduate School of Natural Science and Technology
- Kanazawa University
- Kanazawa 920-1192
- Japan
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14
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Molavian MR, Abdolmaleki A, Firouz Tadavani K, Zhiani M. A new sulfonated poly(ether sulfone) hybrid with low humidity dependence for high-temperature proton exchange membrane fuel cell applications. J Appl Polym Sci 2017. [DOI: 10.1002/app.45342] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
| | - Amir Abdolmaleki
- Department of Chemistry; Isfahan University of Technology; Isfahan 84156-83111 Iran
- Department of Chemistry, College of Sciences; Shiraz University; Shiraz 71467-13565 Iran
| | | | - Mohammad Zhiani
- Department of Chemistry; Isfahan University of Technology; Isfahan 84156-83111 Iran
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15
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Vila JA, Scheraga HA. Limiting Values of the one-bond C-H Spin-Spin Coupling Constants of the Imidazole Ring of Histidine at High-pH. J Mol Struct 2017; 1134:576-581. [PMID: 28919647 PMCID: PMC5596661 DOI: 10.1016/j.molstruc.2017.01.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Assessment of the relative amounts of the forms of the imidazole ring of Histidine (His), namely the protonated (H+) and the tautomeric Nε2-H and Nδ1-H forms, respectively, is a challenging task in NMR spectroscopy. Indeed, their determination by direct observation of the 15N and 13C chemical shifts or the one-bond C-H, 1JCH, Spin-Spin Coupling Constants (SSCC) requires knowledge of the "canonical" limiting values of these forms in which each one is present to the extent of 100%. In particular, at high-pH, an accurate determination of these "canonical" limiting values, at which the tautomeric forms of His coexist, is an elusive problem in NMR spectroscopy. Among different NMR-based approaches to treat this problem, we focus here on the computation, at the DFT level of theory, of the high-pH limiting value for the 1JCH SSCC of the imidazole ring of His. Solvent effects were considered by using the polarizable continuum model approach. The results of this computation suggest, first, that the value of 1JCε1H = 205 ± 1.0 Hz should be adopted as the canonical high-pH limiting value for this SSCC; second, the variation of 1JCε1H SSCC during tautomeric changes is minor, i.e., within ±1Hz; and, finally, the value of 1JCδ2H SSCC upon tautomeric changes is large (15 Hz) indicating that, at high-pH or for non-protonated His at any pH, the tautomeric fractions of the imidazole ring of His can be predicted accurately as a function of the observed value of 1JCδ2H SSCC.
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Affiliation(s)
- Jorge A. Vila
- IMASL-CONICET, Universidad Nacional de San Luis, Ejército de Los Andes 950, 5700-San Luis, Argentina
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16
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Hori Y, Ida T, Mizuno M. Potential energy construction in the diabatic picture for quantum mechanical rate constants of intermolecular proton transfer. Phys Chem Chem Phys 2017. [DOI: 10.1039/c7cp03024j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We propose a simple method for potential construction in the diabatic picture and the estimation of thermal rate constants for intermolecular proton transfer reactions using quantum dynamics simulations carried out on the constructed potentials.
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Affiliation(s)
- Yuta Hori
- Chemistry Course
- Division of Material Chemistry
- Graduate School of Natural Science and Technology
- Kanazawa University
- Kanazawa 920-1192
| | - Tomonori Ida
- Chemistry Course
- Division of Material Chemistry
- Graduate School of Natural Science and Technology
- Kanazawa University
- Kanazawa 920-1192
| | - Motohiro Mizuno
- Chemistry Course
- Division of Material Chemistry
- Graduate School of Natural Science and Technology
- Kanazawa University
- Kanazawa 920-1192
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17
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Feng K, Liu L, Tang B, Li N, Wu P. Nafion-Initiated ATRP of 1-Vinylimidazole for Preparation of Proton Exchange Membranes. ACS APPLIED MATERIALS & INTERFACES 2016; 8:11516-11525. [PMID: 27077232 DOI: 10.1021/acsami.6b02248] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nafion is one of the most widely investigated materials applied in proton exchange membranes. Interestingly, it was found that Nafion could serve as a macroinitiator to induce atom transfer radical polymerization (ATRP) on its C-F sites. In this study, poly(1-vinylimidazole) was selectively bonded on the side chains of Nafion via the Nafion-initiated ATRP process, which was confirmed by the measurements of (1)H/(19)F nuclear magnetic resonance spectra, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, differential scanning calorimeter and matrix-assisted laser desorption ionization-time-of-flight/time-of-flight mass spectrometry. The as-prepared Nafion-co-poly(1-vinylimidazole) (Nafion-PVIm) membranes, with tunable loading amount of imidazole rings, presented greatly enhanced proton conductivity and methanol resistivity due to their well-controlled chemical structures. Especially, chemically bonding PVIm with Nafion chains endowed the Nafion-PVIm membranes with high stability in proton conductivity. For the first time, we revealed the great potentials of the Nafion-initiated ATRP process in developing high-performance proton exchange membranes.
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Affiliation(s)
- Kai Feng
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science and Laboratory of Advanced Materials, Fudan University , Shanghai 200433, People's Republic of China
| | - Lei Liu
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan 030001, People's Republic of China
| | | | - Nanwen Li
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan 030001, People's Republic of China
| | - Peiyi Wu
- State Key Laboratory of Molecular Engineering of Polymers, Collaborative Innovation Center of Polymers and Polymer Composite Materials, Department of Macromolecular Science and Laboratory of Advanced Materials, Fudan University , Shanghai 200433, People's Republic of China
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Cosby T, Holt A, Griffin PJ, Wang Y, Sangoro J. Proton Transport in Imidazoles: Unraveling the Role of Supramolecular Structure. J Phys Chem Lett 2015; 6:3961-3965. [PMID: 26722899 DOI: 10.1021/acs.jpclett.5b01887] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The impact of supramolecular hydrogen bonded networks on dynamics and charge transport in 2-ethyl-4-methylimidazole (2E4MIm), a model proton-conducting system, is investigated by broadband dielectric spectroscopy, depolarized dynamic light scattering, viscometry, and calorimetry. It is observed that the slow, Debye-like relaxation reflecting the supramolecular structure in neat 2E4MIm is eliminated upon the addition of minute amounts of levulinic acid. This is attributed to the dissociation of imidazole molecules and the breaking down of hydrogen-bonded chains, which leads to a 10-fold enhancement of ionic conductivity.
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Affiliation(s)
| | | | - Philip J Griffin
- Department of Materials Science and Engineering, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Yangyang Wang
- Center for Nanophase Materials Science, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
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