1
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Carta P, Scorciapino MA. The combination of inorganic phosphate and pyrophosphate 31 P-NMR for the electrodeless pH determination in the 5-12 range. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2024; 62:101-113. [PMID: 38243872 DOI: 10.1002/mrc.5429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 12/29/2023] [Accepted: 01/01/2024] [Indexed: 01/22/2024]
Abstract
Potentiometry is the primary pH measurement method, but alternatives are sought beyond glass electrodes operative limitations. In nuclear magnetic resonance (NMR) experiments, electrodeless pH sensing is important to track changes along titrations, during chemical reactions or inside compartmentalized environments inaccessible to electrodes, for instance. Although several interesting NMR pH indicators have been already presented, the potential of inorganic phosphate is overlooked, despite its common presence in NMR samples as the buffer main component. Its use for electrodeless pH determination can be expanded by exploiting all its three proton dissociations. This study was aimed at verifying the use of inorganic phosphate 31 P chemical shift to sense pH variations, and at exploring the complementary use of pyrophosphate ions to cover a wide pH range. A simple set of equations is presented to utilize both phosphate and pyrophosphate 31 P chemical shift in combination for accurate pH determination without a glass electrode over the 5-12 pH range, and without affecting the spectrum of other nuclei. The present study demonstrated an average deviation of 0.09 (maximum <0.2) pH unit from glass electrode measurements. The trimethylphosphate can be used as a suitable chemical shift reference for both 31 P and 1 H (also 13 C), with its hydrolysis being significant only at pH > 12. The method was also demonstrated by determining the pKa of three distinct molecules in a mixture and by comparing the results to those obtained when the glass electrode was used to measure the pH. The approach shown here can be easily tuned to different experimental conditions.
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Affiliation(s)
- Paola Carta
- Department of Chemical and Geological Sciences, University of Cagliari, Cittadella di Monserrato, Monserrato, Italy
| | - Mariano Andrea Scorciapino
- Department of Chemical and Geological Sciences, University of Cagliari, Cittadella di Monserrato, Monserrato, Italy
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2
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Rezlerová E, Moučka F, Předota M, Lísal M. Structure and self-diffusivity of alkali-halide electrolytes in neutral and charged graphene nanochannels. Phys Chem Chem Phys 2023; 25:21579-21594. [PMID: 37548441 DOI: 10.1039/d3cp03027j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Understanding the microscopic behaviour of aqueous electrolyte solutions in graphene-based ultrathin nanochannels is important in nanofluidic applications such as water purification, fuel cells, and molecular sensing. Under extreme confinement (<2 nm), the properties of water and ions differ drastically from those in the bulk phase. We studied the structural and diffusion behaviour of prototypical aqueous solutions of electrolytes (LiCl, NaCl, and KCl) confined in both neutral and positively-, and negatively-charged graphene nanochannels. We performed molecular dynamics simulations of the solutions in the nanochannels with either one, two- or three-layer water structures using the effectively polarisable force field for graphene. We analysed the structure and intermolecular bond network of the confined solutions along with their relation to the self-diffusivity of water and ions. The simulations show that Na and K cations can more easily rearrange their solvation shells under the graphene nanoconfinement and adsorb on the graphene surfaces or dissolve in the confinement-induced layered water than the Li cation. The negative surface charge together with the presence of ions orient water molecules with hydrogens towards the graphene surfaces, which in turn weakens the intermolecular bond network. The one-layer nanochannels have the biggest effect on the water structure and intermolecular bonding as well as on the adsorption of ions with only co-ions entering these nanochannels. The self-diffusivity of confined water is strongly reduced with respect to the bulk water and decreases with diminishing nanochannel heights except for the negatively-charged one-layer nanochannel. The self-diffusivity of ions also decreases with the reducing the nanochannel heights except for the self-diffusivity of cations in the negatively-charged one-layer nanochannel, evidencing cooperative diffusion of confined water and ions. Due to the significant break-up of the intermolecular bond network in the negatively-charged one-layer nanochannel, self-diffusion coefficients of water and cations exceed those for the two- and three-layer nanochannels and become comparable to the bulk values.
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Affiliation(s)
- Eliška Rezlerová
- Research Group of Molecular and Mesoscopic Modelling, The Czech Academy of Sciences, Institute of Chemical Process Fundamentals, Prague, Czech Republic.
- Department of Physics, Faculty of Science, Jan Evangelista Purkyně University in Úst nad Labem, Ústín. Lab., Czech Republic
| | - Filip Moučka
- Research Group of Molecular and Mesoscopic Modelling, The Czech Academy of Sciences, Institute of Chemical Process Fundamentals, Prague, Czech Republic.
- Department of Physics, Faculty of Science, Jan Evangelista Purkyně University in Úst nad Labem, Ústín. Lab., Czech Republic
| | - Milan Předota
- Department of Physics, Faculty of Science, University of South Bohemia, České Budě jovice, Czech Republic
| | - Martin Lísal
- Research Group of Molecular and Mesoscopic Modelling, The Czech Academy of Sciences, Institute of Chemical Process Fundamentals, Prague, Czech Republic.
- Department of Physics, Faculty of Science, Jan Evangelista Purkyně University in Úst nad Labem, Ústín. Lab., Czech Republic
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3
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Meng L, Xin N, Hu C, Sabea HA, Zhang M, Jiang H, Ji Y, Jia C, Yan Z, Zhang Q, Gu L, He X, Selvanathan P, Norel L, Rigaut S, Guo H, Meng S, Guo X. Dual-gated single-molecule field-effect transistors beyond Moore's law. Nat Commun 2022; 13:1410. [PMID: 35301285 PMCID: PMC8931007 DOI: 10.1038/s41467-022-28999-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/18/2022] [Indexed: 11/19/2022] Open
Abstract
As conventional silicon-based transistors are fast approaching the physical limit, it is essential to seek alternative candidates, which should be compatible with or even replace microelectronics in the future. Here, we report a robust solid-state single-molecule field-effect transistor architecture using graphene source/drain electrodes and a metal back-gate electrode. The transistor is constructed by a single dinuclear ruthenium-diarylethene (Ru-DAE) complex, acting as the conducting channel, connecting covalently with nanogapped graphene electrodes, providing field-effect behaviors with a maximum on/off ratio exceeding three orders of magnitude. Use of ultrathin high-k metal oxides as the dielectric layers is key in successfully achieving such a high performance. Additionally, Ru-DAE preserves its intrinsic photoisomerisation property, which enables a reversible photoswitching function. Both experimental and theoretical results demonstrate these distinct dual-gated behaviors consistently at the single-molecule level, which helps to develop the different technology for creation of practical ultraminiaturised functional electrical circuits beyond Moore’s law. Conventional silicon-based transistors, which sit at the heart of every computer, are fast approaching the limit of miniaturisation. Here, Meng et al demonstrate a field-effect transistor composed of a single rutheniumdiarylethene molecule with large on/off ratio.
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Affiliation(s)
- Linan Meng
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, Beijing, 100871, PR China.,Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Na Xin
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, Beijing, 100871, PR China
| | - Chen Hu
- Center for the Physics of Materials and Department of Physics, McGill University, Montreal, QC, H3A 2T8, Canada
| | - Hassan Al Sabea
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000, Rennes, France
| | - Miao Zhang
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin, 300350, PR China
| | - Hongyu Jiang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, PR China.,University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Yiru Ji
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, PR China.,University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Chuancheng Jia
- Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin, 300350, PR China
| | - Zhuang Yan
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, Beijing, 100871, PR China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Xiaoyan He
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000, Rennes, France
| | - Pramila Selvanathan
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000, Rennes, France
| | - Lucie Norel
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000, Rennes, France
| | - Stéphane Rigaut
- Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes)-UMR 6226, F-35000, Rennes, France.
| | - Hong Guo
- Center for the Physics of Materials and Department of Physics, McGill University, Montreal, QC, H3A 2T8, Canada.
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, PR China. .,University of Chinese Academy of Sciences, Beijing, 100049, PR China.
| | - Xuefeng Guo
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Center, College of Chemistry and Molecular Engineering, Peking University, 292 Chengfu Road, Haidian District, Beijing, 100871, PR China. .,Center of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Center for New Organic Matter, College of Electronic Information and Optical Engineering, Nankai University, 38 Tongyan Road, Jinnan District, Tianjin, 300350, PR China.
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4
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Sarkar S, Debnath T, Das AK. Reduction of sulfur dioxide using superalkalis: A theoretical perspective. COMPUT THEOR CHEM 2021. [DOI: 10.1016/j.comptc.2021.113317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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5
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Kumar P, Bharti, Rai PK. Synthesis of Environmentally Friendly Rayon‐Graphene Oxide Nano Composite for Decontamination of Water. ChemistrySelect 2021. [DOI: 10.1002/slct.202101338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Pradeep Kumar
- Environment Safety Group Centre for Fire Explosive and Environment Safety (CFEES) Brig. S. K. Mazumdar Road, Timarpur Delhi 110054 India
| | - Bharti
- Environment Safety Group Centre for Fire Explosive and Environment Safety (CFEES) Brig. S. K. Mazumdar Road, Timarpur Delhi 110054 India
| | - Pramod Kumar Rai
- Environment Safety Group Centre for Fire Explosive and Environment Safety (CFEES) Brig. S. K. Mazumdar Road, Timarpur Delhi 110054 India
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6
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Fan X, Teng CP, Yeo JCC, Li Z, Wang T, Chen H, Jiang L, Hou X, He C, Liu J. Temperature and pH Responsive Light-Harvesting System Based on AIE-Active Microgel for Cell Imaging. Macromol Rapid Commun 2021; 42:e2000716. [PMID: 33543517 DOI: 10.1002/marc.202000716] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/14/2021] [Indexed: 11/11/2022]
Abstract
A highly emissive microgel is synthesized by polymerizing tetraphenylethene (TPE) based comonomers, acrylic acid, NIPAM, and permanent crosslinker ethylenebisacrylamide (BIS) (named as TPE microgel), which exhibited temperature responsive fluorescence emission. Rhodamine B (RhB), a positively charged molecule, is then inserted onto the surface of fabricated microgels through electrostatic interaction. As a result, a novel artificial light harvesting system with high energy transfer efficiency is constructed (named as TPE microgel-RhB light harvesting system), which is the first light harvesting system based on TPE microgels presenting dual response to pH and temperature. MTT assay indicates the fabricated TPE microgel and TPE microgel-RhB light harvesting system has good cytocompatibility. The strong fluorescence and good cytocompatibility make them perfect candidates for cell imaging. The prepared emissive microgel and light-harvesting system with desirable fluorescent property not only provide a new strategy for the fabrication of tunable luminescent nanomaterials, but also expand potential applications in the fields of stomach recognition, temperature sensors, and drug delivery.
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Affiliation(s)
- Xiaotong Fan
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576, Singapore
| | - Choon Peng Teng
- Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore, 138634, Singapore
| | - Jayven Chee Chuan Yeo
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576, Singapore.,Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore, 138634, Singapore
| | - Zibiao Li
- Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore, 138634, Singapore
| | - Tingting Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
| | - Haiming Chen
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576, Singapore
| | - Lu Jiang
- Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore, 138634, Singapore
| | - Xunan Hou
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576, Singapore
| | - Chaobin He
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117576, Singapore.,Institute of Materials Research and Engineering, Agency for Science, Technology, and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore, 138634, Singapore
| | - Junqiu Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun, 130012, China
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7
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Kalhor P, Ghandi K, Ashraf H, Yu Z. The structural properties of a ZnCl 2-ethylene glycol binary system and the peculiarities at the eutectic composition. Phys Chem Chem Phys 2021; 23:13136-13147. [PMID: 34075959 DOI: 10.1039/d1cp00573a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
ATR-FTIR spectroscopy was performed on a series of ZnCl2-ethylene glycol (EG) mixtures with a wide-range of compositions (1 : 1.5-1 : 14 in molar ratios), involving the stable ZnCl2-4EG deep-eutectic solvent (DES) composition, to explore the spectral variations, structural heterogeneity, and hydrogen bonding (H-bonding) properties. To enhance the resolution of the spectra, excess absorption and two-dimensional correlation spectroscopies were employed. In the initial IR spectra, a quasi-isosbestic point was identified, signaling that the major disturbance on EG microstructures by adding ZnCl2 is to form a distinct complex. Further analysis uncovered the main transformation process to be from the EG tetramer to the ZnCl2-4EG complex. It was also found that as the EG content increases, negative charge increasingly transfers to ZnCl2, resulting in the strengthening of the Zn ← O coordination bonds and the weakening and finally dissociation of Zn-Cl bonds. Regarding the ZnCl2-4EG DES, several incomparable specificities were observed. It was found that ZnCl2 destructed the H-bonding network of pure EG to the largest extent, resulting in the highest production of the dimer and trimer of EG. Moreover, in comparison with other compositions, the ZnCl2-4EG DES showed abrupt increases in the negative charge of the salt, the length of the Zn-Cl bond, and the strength of the Zn ← O coordination bond. All these imply the strongest intermolecular interactions and the highest solvation of ZnCl2 in EG at the eutectic composition compared to those of other mixtures, resulting in a super-stable liquid mixture. The work provides physical insights into the structural and interactive properties of deep-eutectic solvents.
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Affiliation(s)
- Payam Kalhor
- MOE Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Khashayar Ghandi
- Department of Chemistry, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Hamad Ashraf
- MOE Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
| | - Zhiwu Yu
- MOE Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
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8
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Roucou A, Goubet M, Kleiner I, Bteich S, Cuisset A. Large Amplitude Torsions in Nitrotoluene Isomers Studied by Rotational Spectroscopy and Quantum Chemistry Calculations. Chemphyschem 2020; 21:2523-2538. [PMID: 32857456 DOI: 10.1002/cphc.202000591] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/27/2020] [Indexed: 11/12/2022]
Abstract
Rotational spectra of ortho-nitrotoluene (2-NT) and para-nitrotoluene (4-NT) have been recorded at low and room temperatures using a supersonic jet Fourier Transform microwave (MW) spectrometer and a millimeter-wave frequency multiplier chain, respectively. Supported by quantum chemistry calculations, the spectral analysis of pure rotation lines in the vibrational ground state has allowed to characterise the rotational energy, the hyperfine structure due to the 14 N nucleus and the internal rotation splittings arising from the methyl group. For 2-NT, an anisotropic internal rotation of coupled -CH3 and -NO2 torsional motions was identified by quantum chemistry calculations and discussed from the results of the MW analysis. The study of the internal rotation splittings in the spectra of three NT isomers allowed to characterise the internal rotation potentials of the methyl group and to compare them with other mono-substituted toluene derivatives in order to study the isomeric influence on the internal rotation barrier.
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Affiliation(s)
- Anthony Roucou
- Université du Littoral Côte d'Opale, UR 4493, LPCA, Laboratoire de Physico-Chimie de l'Atmosphère, F-59140, Dunkerque, France.,Institut de la Matière Condensée et des Nanosciences (IMCN), Université catholique de Louvain, Chemin du Cyclotron 2, 1348, Louvain-la-Neuve, Belgium
| | - Manuel Goubet
- Univ. Lille, CNRS, UMR8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000, Lille, France
| | - Isabelle Kleiner
- Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS UMR 7583, Université Paris-Est Créteil & Université de Paris, Institut Pierre Simon Laplace (IPSL), 61 avenue du Général de Gaulle, F-94010, Créteil cedex, France
| | - Sabath Bteich
- Université du Littoral Côte d'Opale, UR 4493, LPCA, Laboratoire de Physico-Chimie de l'Atmosphère, F-59140, Dunkerque, France
| | - Arnaud Cuisset
- Université du Littoral Côte d'Opale, UR 4493, LPCA, Laboratoire de Physico-Chimie de l'Atmosphère, F-59140, Dunkerque, France
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9
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Kalhor P, Zheng YZ, Ashraf H, Cao B, Yu ZW. Influence of Hydration on the Structure and Interactions of Ethaline Deep-Eutectic Solvent: A Spectroscopic and Computational Study. Chemphyschem 2020; 21:995-1005. [PMID: 32232896 DOI: 10.1002/cphc.202000165] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/29/2020] [Indexed: 01/31/2023]
Abstract
Deep-eutectic solvents (DESs) are regarded as alternative green solvents to ionic liquids. In this work we report the structural properties and hydrogen bonding (H-bonding) interactions of an aqueous DES system. The used DES, ethaline (ETH), is composed of choline chloride and ethylene glycol (EG) in 1 : 2 molar ratio. The investigations were carried out by FTIR spectroscopy combined with quantum chemical calculations. Excess spectroscopy and two-dimensional correlation spectroscopy (2D-COS) were used to explore the data in detail. The results showed that, upon mixing, ETH transforms to EG dimers and trimers and D2 O clusters transform to various ETH-D2 O complexes. Theoretical calculations show that water molecules insert between the anion and cation of ETH, break the strong doubly ionic Cl-… H-OCh+ H-bond, share charges of the ions and form H-bond with them, thus modulate the interaction properties of ETH. This study deepens our molecular-level understanding of the system and would shed light on its applications.
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Affiliation(s)
- Payam Kalhor
- MOE Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yan-Zhen Zheng
- College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Hamad Ashraf
- MOE Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Bobo Cao
- MOE Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Zhi-Wu Yu
- MOE Key Laboratory of Bioorganic Phosphorous Chemistry and Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, 100084, China
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10
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Self-preservation and Stability of Methane Hydrates in the Presence of NaCl. Sci Rep 2019; 9:5860. [PMID: 30971725 PMCID: PMC6458167 DOI: 10.1038/s41598-019-42336-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 03/29/2019] [Indexed: 11/16/2022] Open
Abstract
Gas hydrate, a solid transformed from an ensemble of water and gaseous molecules under suitable thermodynamic conditions, is present in marine and permafrost strata. The ability of methane hydrates to exist outside of its standard stability zone is vital in many aspects, such as its utility in gas storage and transportation, hydrate-related climate changes and gas reservoirs on the planet. A systematic study on the stability of methane hydrates divulges that the gas uptake decreased by about 10% by increasing the NaCl content to 5.0 wt%. The hydrate formation kinetic is relatively slower in a system with higher NaCl. The self-preservation temperature window for hydrate systems with NaCl 1.5, 3.0 and 5.0 wt% dramatically shifted to a lower temperature (252 K), while it remained around 270 K for NaCl 0.0 and 0.5 wt%. Based on powder x-ray diffraction and micro-Raman spectroscopic studies, the presence of hydrohalite (NaCl·2H2O) phase was identified along with the usual hydrate and ice phases. The eutectic melting of this mixture is responsible for shifting the hydrate stability to 252 K. A systematic lattice expansion of cubic phase infers the interaction between NaCl and water molecules of hydrate cages.
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11
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12
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Varadwaj A, Varadwaj PR, Marques HM, Yamashita K. A DFT assessment of some physical properties of iodine-centered halogen bonding and other non-covalent interactions in some experimentally reported crystal geometries. Phys Chem Chem Phys 2018; 20:15316-15329. [PMID: 29796486 DOI: 10.1039/c8cp01085d] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A set of six binary complexes that feature iodine-centered halogen bonding, extracted from structures deposited in the Cambridge Structure Database, has been examined computationally using density functional theory calculations with the M06-2X global hybrid, and dispersion corrected B3LYP-D3 and B97-D3, to determine their equilibrium geometries, binding energies and electronic properties. The results show that gas phase calculations are very informative in evaluating what occurs in the solid state, even though these calculations ignore the importance of lattice packing and counter ion effects. The calculated binding energies for the non-covalent interactions responsible for these complexes lie between -4.15 and -7.48 kcal mol-1 (M06-2X), which enables us to characterize them as weak-to-moderate in strength. The basis set superposition error energies are calculated to vary between 0.60 and 2.42 kcal mol-1 for all the complexes examined, even though an all-electron QZP basis set used in the analysis was of quadrupole-ζ (plus polarization) quality. Dispersion is found to have a profound effect on the binding energy of some of these complexes, and was estimated to be as large as 5.0 kcal mol-1. For one complex, the crystal geometry could not be precisely reproduced using a gas phase calculation. While both halogen- and hydrogen-bonding interactions were found competitive, they cooperate with each other to determine the stable configuration of the binary complex. The molecular electrostatic surface potential, quantum theory of atoms in molecules, and reduced density gradient non-covalent Interaction models were utilized to arrive at a fundamental understanding of the various inter- and intra-molecular molecular interactions involved, as well as some other previously-overlooked non-covalent interactions that emerge in the modelling.
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Affiliation(s)
- Arpita Varadwaj
- Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, 113-8656, Japan.
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13
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Emami M, Ślepokura KA, Trzebiatowska M, Noshiranzadeh N, Kinzhybalo V. Oxyanion clusters with antielectrostatic hydrogen bonding (AEHB) in tetraalkylammonium hypodiphosphates. CrystEngComm 2018. [DOI: 10.1039/c8ce00880a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Organic–inorganic salts of hypodiphosphoric acid with tetraalkylammonium cations have been synthesized and characterized by X-ray crystallography and IR spectroscopy.
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Affiliation(s)
- Marzieh Emami
- Department of Chemistry
- Faculty of Sciences
- University of Zanjan
- Zanjan
- Iran
| | | | - Monika Trzebiatowska
- Institute of Low Temperature and Structure Research
- Polish Academy of Sciences
- 50-422 Wrocław
- Poland
| | | | - Vasyl Kinzhybalo
- Institute of Low Temperature and Structure Research
- Polish Academy of Sciences
- 50-422 Wrocław
- Poland
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14
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Singh H, Topsakal M, Attenkofer K, Wolf T, Leskes M, Duan Y, Wang F, Vinson J, Lu D, Frenkel AI. Identification of dopant site and its effect on electrochemical activity in Mn-doped lithium titanate. PHYSICAL REVIEW MATERIALS 2018; 2:10.1103/PhysRevMaterials.2.125403. [PMID: 31093600 PMCID: PMC6513013 DOI: 10.1103/physrevmaterials.2.125403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Doped metal oxide materials are commonly used for applications in energy storage and conversion, such as batteries and solid oxide fuel cells. The knowledge of the electronic properties of dopants and their local environment is essential for understanding the effects of doping on the electrochemical properties. Using a combination of X-ray absorption near-edge structure spectroscopy (XANES) experiment and theoretical modeling we demonstrate that in the dilute (1 at. %) Mn-doped lithium titanate (Li4/3Ti5/3O4, or LTO) the dopant Mn2+ ions reside on tetrahedral (8a) sites. First-principles Mn K-edge XANES calculations revealed the spectral signature of the tetrahedrally coordinated Mn as a sharp peak in the middle of the absorption edge rise, caused by the 1s → 4p transition, and it is important to include the effective electron-core hole Coulomb interaction in order to calculate the intenisty of this peak accurately. This dopant location explains the impedance of Li migration through the LTO lattice during the charge-discharge process, and, as a result - the observed remarkable 20% decrease in electrochemical rate performance of the 1% Mn-doped LTO compared to the pristine LTO.
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Affiliation(s)
- Harishchandra Singh
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, United States
| | - Mehmet Topsakal
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Klaus Attenkofer
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Tamar Wolf
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michal Leskes
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yandong Duan
- Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Feng Wang
- Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - John Vinson
- Materials Measurement Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Deyu Lu
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Anatoly I. Frenkel
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, United States
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States
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