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Srinivasan H, Sharma VK, Sakai VG, Mukhopadhyay R, Mitra S. Noncanonical Relationship between Heterogeneity and the Stokes-Einstein Breakdown in Deep Eutectic Solvents. J Phys Chem Lett 2023; 14:9766-9773. [PMID: 37882461 DOI: 10.1021/acs.jpclett.3c02132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
The relationship between Stokes-Einstein breakdown (SEB) and dynamical heterogeneity (DH) is of paramount importance in the physical chemistry of complex fluids. In this work, we employ neutron scattering to probe the DH and SEB in a series of deep eutectic solvents (DESs) composed of acetamide and lithium salts. Quasielastic neutron scattering experiments reveal SEB in the jump diffusion of acetamide, represented by a fractional Stokes-Einstein relationship. Among these DESs, lithium perchlorate exhibits the most pronounced SEB while lithium bromide displays the weakest. Concurrently, elastic incoherent neutron scans identify that bromide DES is the most heterogeneous and perchlorate is the least. For the first time, our study unveils a counterintuitive incommensurate relationship between DH and SEB. Further, it reveals the intricate contrasting nature of the SEB-DH relationship when investigated in proximity to the glass-transition temperature and further away from it.
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Affiliation(s)
- H Srinivasan
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - V K Sharma
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - V García Sakai
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K
| | - R Mukhopadhyay
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - S Mitra
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
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Buchner R, Agieienko V. Ethaline and related systems: may be not “deep” eutectics but clearly interesting ionic liquids. PURE APPL CHEM 2023. [DOI: 10.1515/pac-2022-1112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Abstract
Ethaline, the 1:2 molar ratio mixture of ethylene glycol (EG) and choline chloride (ChCl), is generally regarded as a typical type III deep eutectic solvent (DES). However, careful differential scanning calorimetry (DSC) of EG + ChCl mixtures surprisingly revealed that the liquidus lines of the phase diagram apparently follow the predictions for an ideal binary non-electrolyte mixture. Applying broad-band dielectric relaxation spectroscopy to room-temperature solutions of ChCl, and of the related salts choline iodide and chlorocholine chloride, in EG up to saturation, we explored the possible reasons for this conundrum. It appears that in these solutions free ions are rather scarce. Instead, contact ion pairs and larger aggregates predominate.
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Affiliation(s)
- Richard Buchner
- Physical & Theoretical Chemistry , Universität Regensburg , Regensburg , Germany
| | - Vira Agieienko
- Nanotechnology and Biotechnology Department , Nizhny Novgorod State Technical University n a R E Alekseev , Niznij Novgorod , Nižegorodskaâ , Russian Federation
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Długosz O. Natural Deep Eutectic Solvents in the Synthesis of Inorganic Nanoparticles. MATERIALS (BASEL, SWITZERLAND) 2023; 16:627. [PMID: 36676363 PMCID: PMC9862785 DOI: 10.3390/ma16020627] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/23/2022] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
Natural deep eutectic solvents (NDESs), as a new type of green solvent, are used in many fields, including industry in extraction processes, medicine, pharmaceuticals, metallurgy, electrodeposition, separations, gas capture, biocatalysis and nanotechnology. Mainly due to their properties, such as simple preparation, environmental friendliness, biocompatibility and multifunctionality, they are being used in various fields of industry. This review aims to provide insight into the applications of natural deep eutectic solvents, specifically in nanotechnology processes. It focuses on the description of NDES and how their physicochemical properties are used to obtain functional nanomaterials, including metals, metal oxides and salts. It highlights how the use of NDESs to obtain a wide range of inorganic nanoparticles enables the elimination of disadvantages of traditional methods of obtaining them, including reducing energy consumption and functionalising nanoparticles in situ. In conclusion, recent advances and future directions in the development and applications of NDESs in nanotechnology are discussed with the aim of identifying unexplained scientific questions that can be investigated in the future.
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Affiliation(s)
- Olga Długosz
- Faculty of Chemical Engineering and Technology, Cracow University of Technology, 31-155 Cracow, Poland
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Agieienko V, Neklyudov V, Buchner R. Why Does Ethaline Apparently Behave as an Ideal Binary Mixture? J Phys Chem Lett 2022; 13:10805-10809. [PMID: 36375079 DOI: 10.1021/acs.jpclett.2c02901] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Phase diagram mixtures of the salt choline chloride (ChCl) with ethylene glycol (EG) surprisingly seem to behave as ideal binary nonelectrolyte mixtures [Agieienko, V.; Buchner, R. Phys. Chem. Chem. Phys.2022, 24, 5265]. To shed some light on this conundrum, results of broad-band dielectric relaxation spectroscopy (DRS) and quantum-chemical calculations are reported for solutions of ChCl, choline iodide (ChI), and chlorocholine chloride (ClChCl), in EG up to saturation at 298.15 K. The data revealed that all three solutes are only weakly solvated in the sense that on average per equivalent of solute only one EG OH-group is dynamically affected. While contact ion pairs are significant for solute concentrations of ≲1 M, free cation concentrations are rather low. Instead, over the entire concentration range a large fraction of the dipolar cations could not be detected by DRS. We argue that the latter are embedded in large solute aggregates, explaining thus the phase diagram of ChCl + EG and the very low ionicity of all systems.
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Affiliation(s)
- Vira Agieienko
- Laboratory of Engineering Chemistry, Research Institute for Chemistry, Lobachevsky State University of Nizhny Novgorod, 23 Gagarina av., 603022Nizhny Novgorod, Russia
- Laboratory of Membrane and Catalytic Processes, Nanotechnology and Biotechnology Department, Nizhny Novgorod State Technical University n.a. R.E. Alekseev, 24 Minin str., 603950Nizhny Novgorod, Russia
| | - Vadim Neklyudov
- Wolfson Department of Chemical Engineering, Technion─IIT, Haifa32000, Israel
| | - Richard Buchner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, D-93040Regensburg, Germany
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Srinivasan H, Sharma VK, Mitra S. Modulation of Diffusion Mechanism and Its Correlation with Complexation in Aqueous Deep Eutectic Solvents. J Phys Chem B 2022; 126:9026-9037. [PMID: 36315464 DOI: 10.1021/acs.jpcb.2c05312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Aqueous mixtures of deep eutectic solvents (DESs) have gained traction recently as an effective template to tailor their physicochemical properties. But detailed microscopic insights into the effects of water on the molecular relaxation phenomenon in DESs are not entirely understood. DESs are strong network-forming liquids due to the extensive hydrogen bonding and complex formation between their species, and therefore, water can behave as a controlled disruptor altering the microscopic structure and dynamics in DESs. In this study, the role of water in the diffusion mechanism of acetamide in the aqueous mixtures of DESs synthesized using acetamide and lithium perchlorate is investigated using molecular dynamics (MD) simulation and quasielastic neutron scattering (QENS). The acetamide dynamics comprises localized diffusion within transient cages and a jump diffusion process across cages. The jump diffusion process is observed to be strongly enhanced by about a factor of 10 as the water content in the system is increased. Meanwhile, the geometry of the localized dynamics is unaltered by addition of water, but the localized diffusion becomes significantly faster and more heterogeneous with increasing water concentration. The accelerating effects of water on localized diffusion are also substantiated by QENS experiments. The water concentration in the DES is observed to control the solvation structure of lithium ions, with the ions becoming significantly hydrated at 20 wt % water. The formation of interwater and water-acetamide hydrogen bonds is observed. The increase in water concentration is found to increase the number of H-bonds; however, their lifetimes are found to decrease substantially. Similarly, the lifetimes of acetamide-lithium complexes are also found to be diminished by increasing water concentration. A power-law scaling relationship between lifetimes and diffusion constants is established, elucidating the extent of coupling between diffusive processes and hydrogen bonding and microscopic complexation. This study demonstrates the ability to use water as an agent to probe the role of structural relaxation and complex lifetimes of diffusive processes at different time and length scales.
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Affiliation(s)
- H Srinivasan
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai400085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
| | - V K Sharma
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai400085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
| | - S Mitra
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai400085, India.,Homi Bhabha National Institute, Anushaktinagar, Mumbai400094, India
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Hinz Y, Böhmer R. Deuteron magnetic resonance study of glyceline deep eutectic solvents: Selective detection of choline and glycerol dynamics. J Chem Phys 2022; 156:194506. [PMID: 35597634 DOI: 10.1063/5.0088290] [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
Glyceline, a green solvent considered for various electrochemical applications, represents a multi-component glass former. Viewed from this perspective, the choline cation and the hydrogen bond donor glycerol, the two major constituents forming this deep eutectic solvent, were studied using nuclear magnetic resonance in a selective manner by means of suitably deuteron-labeled isotopologues. Carried out from far above to far below the glass transition temperature, measurements and analyses of the spin-lattice and spin-spin relaxation times reveal that the reorientational dynamics of the components, i.e., of glycerol as well as of chain deuterated choline chloride are slightly different. Possible implications of this finding regarding the hydrogen-bonding pattern in glyceline are discussed. Furthermore, the deuterated methyl groups in choline chloride are exploited as sensitive probes of glyceline's supercooled and glassy states. Apart from spin relaxometry, a detailed line shape analysis of the CD3 spectra yields valuable insights into the broad intermolecular and intramolecular energy barrier distributions present in this binary mixture.
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Affiliation(s)
- Yannik Hinz
- Experimental Physics III, Technical University Dortmund, D-44221 Dortmund, Germany
| | - Roland Böhmer
- Experimental Physics III, Technical University Dortmund, D-44221 Dortmund, Germany
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