1
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Wong LN, Brunner M, Imberti S, Warr GG, Atkin R. Bulk Nanostructure of Mixtures of Choline Arginate, Choline Lysinate, and Water. J Phys Chem B 2024. [PMID: 38691762 DOI: 10.1021/acs.jpcb.4c01482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
Neutron diffraction with empirical potential structure refinement was used to investigate the bulk liquid nanostructure of mixtures of choline arginate (Ch[Arg]), choline lysinate (Ch[Lys]), and water at mole ratios of 1Ch[Arg]:1Ch[Lys]:6H2O (balanced), 1Ch[Arg]:1Ch[Lys]:20H2O (balanced dilute), 3Ch[Arg]:1Ch[Lys]:12H2O (Arg- rich), and 1Ch[Arg]:3Ch[Lys]:12H2O (Lys- rich). The Arg- and Lys- anions tend not to associate due to electrostatic repulsion between charge groups and weak anion-anion attractions. This means that the local ion structures around the anions in these mixtures resemble the parent single-component systems. The bulk liquid nanostructure varies with the Arg-:Lys- ratio. In the Lys--rich mixture (1Ch[Arg]:3Ch[Lys]:12H2O), Lys- side chains cluster into a continuous apolar domain separated from a charged domain of polar groups. In the balanced mixture (1Ch[Arg]:1Ch[Lys]:6H2O), Lys- side chains form discrete apolar aggregates within a continuous polar domain of Arg-, Ch+, and water, and in the Arg--rich mixture (3Ch[Arg]:1Ch[Lys]:12H2O), the distribution of Lys- and Arg- is nearly homogeneous. Finally, in the balance dilute system (1Ch[Arg]:1Ch[Lys]:20H2O), a percolating water domain forms.
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Affiliation(s)
- Lucas N Wong
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Manuel Brunner
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Silvia Imberti
- UKRI, STFC, ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Gregory G Warr
- School of Chemistry and University of Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
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2
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Kahlon NK, Matthewman EL, El Mohamad M, Greaves TL, Weber CC. Small-Angle X-ray Scattering Study of the Amphiphilic Bulk Nanostructure of Tetraalkylammonium Deep Eutectic Solvents. J Phys Chem B 2024. [PMID: 38662201 DOI: 10.1021/acs.jpcb.4c00943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Deep eutectic solvents (DESs) are low-melting mixtures, often prepared from a salt and a molecular hydrogen bond donor. Like ionic liquids, DESs that contain at least one sufficiently amphiphilic component can form bicontinuous nanostructures consisting of polar and nonpolar domains, although this has not been widely explored for many DES combinations. Here, the bulk nanostructures of DESs comprising tetraalkylammonium bromide salts (tetrabutylammonium bromide, tetraoctylammonium bromide, and methyltrioctylammonium bromide) with alkanols and alkanoic acids of systematically varied chain lengths (C2, C6, C8, and C10) as hydrogen bond donors have been studied. Small-angle X-ray scattering techniques were used to identify the relationship between the alkyl chain length and functionality of the hydrogen bond donor on the nature of the amphiphilic nanostructures formed. These findings demonstrated that the amphiphilic nanostructures of the DESs were not affected by the functional group on the hydrogen bond donor, with these nanostructures influenced primarily by both the absolute and relative alkyl chain lengths of the salt and hydrogen bond donor.
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Affiliation(s)
- Navjot K Kahlon
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | - Emma L Matthewman
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
| | | | | | - Cameron C Weber
- School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand
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3
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Izquierdo S, Cintas P, Durán-Valle CJ, de la Concepción JG, López-Coca IM. Reinvigorating aza-Michael reactions under ionic liquid catalysis: a greener approach. Org Biomol Chem 2024; 22:2423-2434. [PMID: 38415317 DOI: 10.1039/d3ob02006a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Cholinium α-amino carboxylates, which debuted in the ionic liquid arena over a decade ago, exhibit superior stability and suitable physical properties relative to other RTILs. Although synthetic pursuits in such media, leveraging their dual role as solvents and catalysts, have been scarce so far, we herein illustrate their catalytic advantage in aza-Michael reactions in terms of low loading, acceleration and improved yields with respect to conventional conditions and other imidazolium-based ILs. These highly structured salts most likely act through multiple and cooperative non-covalent interactions. These mechanistic features have also been investigated through high-level computational analyses as well.
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Affiliation(s)
- Silvia Izquierdo
- Department of Organic and Inorganic Chemistry, School of Technology and INTERRA-Sustainable and Environmental Chemistry Lab, Universidad de Extremadura, 10003-Cáceres, Spain.
| | - Pedro Cintas
- Department of Organic and Inorganic Chemistry, Faculty of Sciences and IACYS-Green Chemistry and Sustainable Development Unit, Universidad de Extremadura, 06006-Badajoz, Spain
| | - Carlos J Durán-Valle
- Department of Organic and Inorganic Chemistry, Faculty of Sciences and IACYS-Green Chemistry and Sustainable Development Unit, Universidad de Extremadura, 06006-Badajoz, Spain
| | - Juan García de la Concepción
- Department of Organic and Inorganic Chemistry, Faculty of Sciences and IACYS-Green Chemistry and Sustainable Development Unit, Universidad de Extremadura, 06006-Badajoz, Spain
| | - Ignacio M López-Coca
- Department of Organic and Inorganic Chemistry, School of Technology and INTERRA-Sustainable and Environmental Chemistry Lab, Universidad de Extremadura, 10003-Cáceres, Spain.
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4
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Wong LN, Imberti S, Warr GG, Atkin R. Bulk nanostructure of a deep eutectic solvent with an amphiphilic hydrogen bond donor. Phys Chem Chem Phys 2023; 25:31068-31076. [PMID: 37946570 DOI: 10.1039/d3cp03587e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Neutron diffraction with empirical potential structure refinement (EPSR) show the deep eutectic solvent (DES) 1 : 4 choline chloride : butyric acid is amphiphilically nanostructured. Nanostructure results from solvophobic interactions between the alkyl chains of the butyric acid hydrogen bond donor (HBD) and is retained with addition of 10 wt% water. EPSR fits to the diffraction data is used to produce a three-dimensional model of the liquid which is interrogated to reveal the interactions leading to the solvophobic effect, and therefore nanostructure, in this DES at atomic resolution. The model shows electrostatic and hydrogen bond interactions cause the cation, anion and HBD acid group to cluster into a polar domain, from which the acid alkyl chains are solvophobically excluded into theapolar domain. The polar and apolar domains percolate through the liquid in a bicontinuous sponge-like structure. The effect of adding 10 wt% water is probed, revealing that water molecules are sequestered around the cation and anion within the polar domain, while the neat bulk structure is retained. Alkyl chain packing in the apolar domain becomes slightly better-defined indicating water marginally strengthens solvophobic segregation. These findings reveal bulk self-assembled nanostructure can be produced in DESs via an amphiphilic HBD.
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Affiliation(s)
- Lucas N Wong
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia.
| | - Silvia Imberti
- STFC, ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Gregory G Warr
- School of Chemistry and University of Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Crawley, Perth 6009, Australia.
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Wang J, Buzolic JJ, Mullen JW, Fitzgerald PA, Aman ZM, Forsyth M, Li H, Silvester DS, Warr GG, Atkin R. Nanostructure of Locally Concentrated Ionic Liquids in the Bulk and at Graphite and Gold Electrodes. ACS NANO 2023; 17:21567-21584. [PMID: 37883191 DOI: 10.1021/acsnano.3c06609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
Abstract
The physical properties of ionic liquids (ILs) have led to intense research interest, but for many applications, high viscosity is problematic. Mixing the IL with a diluent that lowers viscosity offers a solution if the favorable IL physical properties are not compromised. Here we show that mixing an IL or IL electrolyte (ILE, an IL with dissolved metal ions) with a nonsolvating fluorous diluent produces a low viscosity mixture in which the local ion arrangements, and therefore key physical properties, are retained or enhanced. The locally concentrated ionic liquids (LCILs) examined are 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HMIM TFSI), 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate (HMIM FAP), or 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate (BMIM FAP) mixed with 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (TFTFE) at 2:1, 1:1, and 1:2 (w/w) IL:TFTFE, as well as the locally concentrated ILEs (LCILEs) formed from 2:1 (w/w) HMIM TFSI-TFTFE with 0.25, 0.5, and 0.75 m lithium bis(trifluoromethylsulfonyl)imide (LiTFSI). Rheology and conductivity measurements reveal that the added TFTFE significantly reduces viscosity and increases ionic conductivity, and cyclic voltammetry (CV) reveals minimal reductions in electrochemical windows on gold and carbon electrodes. This is explained by the small- and wide-angle X-ray scattering (S/WAXS) and atomic force microscopy (AFM) data, which show that the local ion nanostructures are largely retained in LCILs and LCILEs in bulk and at gold and graphite electrodes for all potentials investigated.
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Affiliation(s)
- Jianan Wang
- School of Molecular Sciences, The University of Western Australia, Perth 6009, Australia
| | - Joshua J Buzolic
- School of Molecular Sciences, The University of Western Australia, Perth 6009, Australia
| | - Jesse W Mullen
- School of Molecular and Life Sciences, Curtin University, Perth 6102, Australia
| | - Paul A Fitzgerald
- Sydney Analytical, Core Research Facilities, The University of Sydney, Sydney 2050, Australia
| | - Zachary M Aman
- Department of Chemical Engineering, The University of Western Australia, Perth 6009, Australia
| | - Maria Forsyth
- Institute for Frontier Materials and the ARC Centre of Excellence for Electromaterials Science, Deakin University, Geelong 3220, Australia
| | - Hua Li
- School of Molecular Sciences, The University of Western Australia, Perth 6009, Australia
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth 6009, Australia
| | - Debbie S Silvester
- School of Molecular and Life Sciences, Curtin University, Perth 6102, Australia
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute, The University of Sydney, Sydney 2050, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth 6009, Australia
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Oluwole SA, Veríssimo NV, Denis AA, Garcia NT, Fura S, Jayaraman K, Valles JD, Del Rosario DH, Patel PN, Duran A, Hakim QA, Quintana AA, Agatemor C. Unusual photophysics of geranic acid deep eutectic solvents. Chem Commun (Camb) 2023; 59:10492-10495. [PMID: 37566436 DOI: 10.1039/d3cc02457a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
The photophysics of natural deep eutectic solvents (NADESs) remains unexplored. Here, we report that a class of NADESs aggregates in water, enabling through-space interaction as evidenced by an unusual emission and redshifted UV absorption band. The NADESs enhanced fluorescence excitation and emission of fluorogenic proteins for improved bioimaging.
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Affiliation(s)
| | | | - Amina A Denis
- Department of Chemistry, University of Miami, Coral Gables, FL, USA.
| | | | - Samuel Fura
- Department of Chemistry, University of Miami, Coral Gables, FL, USA.
| | | | | | | | | | | | | | | | - Christian Agatemor
- Department of Chemistry, University of Miami, Coral Gables, FL, USA.
- Department of Biology, University of Miami, Coral Gables, FL, USA
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA
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Dhattarwal HS, Kashyap HK. Microstructures of Choline Amino Acid based Biocompatible Ionic Liquids. CHEM REC 2023; 23:e202200295. [PMID: 36960931 DOI: 10.1002/tcr.202200295] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/26/2023] [Indexed: 03/25/2023]
Abstract
Bio-compatible ionic liquids (Bio-ILs) represent a class of solvents with peculiar properties and exhibit huge potential for their applications in different fields of chemistry. Ever since they were discovered, researchers have used bio-ILs in diverse fields such as biomass dissolution, CO2 sequestration, and biodegradation of pesticides. This review highlights the ongoing research studies focused on elucidating the microscopic structure of bio-ILs based on cholinium cation ([Ch]+ ) and amino acid ([AA]- ) anions using the state-of-the-arta b i n i t i o ${ab\hskip0.25eminitio}$ and classical molecular dynamics (MD) simulations. The microscopic structure associated with these green ILs guides their suitability for specific applications. ILs of this class differ in the side chain of the amino acid anions, and varying the side chain significantly affects the structure of these ILs and thus helps in tuning the efficiency of biomass dissolution. This review demonstrates the central role of the side chain on the morphology of choline amino acid ([Ch][AA]) bio-ILs. The seemingly matured field of bio-ILs and their employment in various applications still holds significant potential, and the insights on their microscopic structure would steer the field of target specific application of these green ILs.
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Affiliation(s)
- Harender S Dhattarwal
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Hemant K Kashyap
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
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Marlow JB, Atkin R, Warr GG. How Does Nanostructure in Ionic Liquids and Hybrid Solvents Affect Surfactant Self-Assembly? J Phys Chem B 2023; 127:1490-1498. [PMID: 36786772 DOI: 10.1021/acs.jpcb.2c07458] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Ionic liquids (ILs) have recently emerged as novel classes of solvents that support surfactant self-assembly into micelles, liquid crystals, and microemulsions. Their low volatility and wide liquid stability ranges make them attractive for many diverse applications, especially in extreme environments. However, the number of possible ion combinations makes systematic investigations both challenging and rare; this is further amplified when mixtures are considered, whether with water or other H-bonding components such as those found in deep eutectics. In this Perspective we examine what factors determine amphiphilicity, solvophobicity and solvophilicity, in ILs and related exotic environments, in what ways these differ from water, and how the underlying nanostructure of the liquid itself affects the formation and structure of micelles and other self-assembled materials.
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Affiliation(s)
- Joshua B Marlow
- School of Chemistry and Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Gregory G Warr
- School of Chemistry and Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia
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Zhang Y, Zhang X, Tang S, Wang Y, Li H, Mochizuki K, Yao J. Relationship between Structure and Properties of Nonstoichiometric Protic Ionic Liquids: n-Butylammonium Butyrate System. J Phys Chem Lett 2022; 13:10107-10113. [PMID: 36269300 DOI: 10.1021/acs.jpclett.2c02526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Nonstoichiometric protic ionic liquids have drawn much attention in applications, including fuel cells, batteries, and reaction media. An understanding of the relationship between their structure and properties is instructive for further applications. However, there are only a few studies on nonstoichiometric protic ionic liquids. Herein, the density, viscosity, and conductivity of nonstoichiometric n-butylammonium butyrate protic ionic liquids were measured, and we used small/wide-angle scattering (S/WAXS), electron paramagnetic resonance (EPR), and molecular dynamics (MD) simulation to explore the effect of mesostructure on their properties. It is found that the hydrogen bonds drive excess N-butyric acid (PrCOOH) molecules to wrap around ion clusters, resulting in the higher density and viscosity of PrCOOH-rich PILs. The microenvironments around various radicals differ significantly in BuNH2-rich and PrCOOH-rich PILs because of the distinct molecular arrangements. This research provided a link between the physicochemical properties and structures of nonstoichiometric PILs, which is essential for their applications in electrolytes and organic reactions.
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Affiliation(s)
- Yue Zhang
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
- ZJU-NHU United R&D Center, Zhejiang University, Hangzhou 310027, P.R. China
| | - Xuan Zhang
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
| | - Shiyi Tang
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
| | - Yongtao Wang
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
- ZJU-NHU United R&D Center, Zhejiang University, Hangzhou 310027, P.R. China
| | - Haoran Li
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
- ZJU-NHU United R&D Center, Zhejiang University, Hangzhou 310027, P.R. China
- State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, P.R. China
| | - Kenji Mochizuki
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
| | - Jia Yao
- Department of Chemistry, Zhejiang University, Hangzhou 310027, P.R. China
- ZJU-NHU United R&D Center, Zhejiang University, Hangzhou 310027, P.R. China
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Quintana AA, Sztapka AM, Santos Ebinuma VDC, Agatemor C. Enabling Sustainable Chemistry with Ionic Liquids and Deep Eutectic Solvents: A Fad or the Future? Angew Chem Int Ed Engl 2022; 61:e202205609. [PMID: 35789078 DOI: 10.1002/anie.202205609] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Indexed: 12/17/2022]
Abstract
Ionic liquids (ILs) and deep eutectic solvents (DESs) debuted with a promise of a superior sustainability footprint due to their low vapor pressure. However, their toxicity and high cost compromise this footprint, impeding their real-world applications. Fortunately, their property tunability through a rational selection of precursors, including bioderived ones, provides a strategy to ameliorate toxicity, lower cost, and endow new functions. This Review discusses whether ILs and DESs are sustainable solvents and how they contribute to sustainable chemical processes.
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Affiliation(s)
| | | | - Valéria de Carvalho Santos Ebinuma
- Department of Engineering of Bioprocesses and Biotechnology, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Christian Agatemor
- Department of Chemistry, University of Miami, Coral Gables, FL 33124, USA.,Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL 33136, USA
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Agatemor C, Quintana AA, Sztapka LM, Ebinuma VDCS. Enabling Sustainable Chemistry with Ionic Liquids and Deep Eutectic Solvents: a Fad or the Future? Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202205609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Christian Agatemor
- University of Miami - Coral Gables Campus: University of Miami Chemistry 1301 Memorial Dr 33146 Coral Gables UNITED STATES
| | - Aline Andrea Quintana
- University of Miami - Coral Gables Campus: University of Miami Chemistry UNITED STATES
| | - Lani Maria Sztapka
- University of Miami - Coral Gables Campus: University of Miami Chemistry UNITED STATES
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14
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Bodo E. Perspectives in the Computational Modeling of New Generation, Biocompatible Ionic Liquids. J Phys Chem B 2022; 126:3-13. [PMID: 34978449 PMCID: PMC8762658 DOI: 10.1021/acs.jpcb.1c09476] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/15/2021] [Indexed: 12/11/2022]
Abstract
In this Perspective, I review the current state of computational simulations on ionic liquids with an emphasis on the recent biocompatible variants. These materials are used here as an example of relatively complex systems that highlights the limits of some of the approaches commonly used to study their structure and dynamics. The source of these limits consists of the coexistence of nontrivial electrostatic, many-body quantum effects, strong hydrogen bonds, and chemical processes affecting the mutual protonation state of the constituent molecular ions. I also provide examples on how it is possible to overcome these problems using suitable simulation paradigms and recently improved techniques that, I expect, will be gradually introduced in the state-of-the-art of computational simulations of ionic liquids.
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Affiliation(s)
- Enrico Bodo
- Chemistry Department, University of Rome “La Sapienza”, P. A. Moro 5, 00185 Rome, Italy
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15
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Brunner M, Garvey CJ, Warr GG, Atkin R. Conformation of poly(ethylene glycol) in aqueous cholinium amino acid hybrid solvents. J Colloid Interface Sci 2021; 602:334-343. [PMID: 34139531 DOI: 10.1016/j.jcis.2021.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/20/2021] [Accepted: 06/02/2021] [Indexed: 11/30/2022]
Abstract
HYPOTHESIS Hybrid solvents based on cholinium amino acid ionic liquids ([Ch][AA] ILs) mixed with water are environmentally benign solvents with low toxicity. [Ch][AA] ILs are used in biomass pretreatment processes to dissolve targeted (macro)molecules such as lignin from lingnocellulose. Understanding how [Ch][AA] ILs dissolve polymers is therefore of great interest for the rational design of ILs towards industrial application. Variation of the IL anion and the water concentration are hypothesised to change the solvent properties of [Ch][AA] hybrid solvents. Therefore, we probe the solvent quality of [Ch][AA] aqueous solutions with different anions (glycinate, prolinate and argininate) and water concentration for the simple model solute poly(ethylene glycol) (PEG). EXPERIMENTS Partial phase diagrams were produced to probe the salting-out effect of [Ch][AA] ILs towards PEG (Mw = 38 kDa). Small-angle neutron scattering experiments of deuterated PEG in hydrogenous [Ch][AA] aqueous solutions were performed to determine the polymer radius of gyration at infinite dilution (Rg,0) via Zimm-plots. Polymer concentration dependent apparent Rg values were obtained fitting an excluded volume polymer model onto the scattering data. Blends of hydrogenous and deuterated PEG under zero average contrast conditions were analysed to probe Rg at high polymer concentrations. FINDINGS Hydrogen bond capacity of the anion is key to the salting-out effect of [Ch][AA] ILs on PEG. Rg,0 depends on anion species and water concentration. At IL:water = 1:30 (mole:mole) and 37 °C, cholinium argininate and cholinium glycinate are close to theta solvents while cholinium prolinate and dilute cholinium argininate (IL:water = 1:100) are between theta and good solvents.
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Affiliation(s)
- Manuel Brunner
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia.
| | - Christopher J Garvey
- Lund Institute for Advanced Neutron and X-ray Science, 223 70 Lund, Sweden; Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany.
| | - Gregory G Warr
- School of Chemistry and University of Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia.
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia.
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16
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Betaine and l-carnitine ester bromides: Synthesis and comparative study of their thermal behaviour and surface activity. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115988] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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17
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Miao S, Jiang HJ, Imberti S, Atkin R, Warr G. Aqueous choline amino acid deep eutectic solvents. J Chem Phys 2021; 154:214504. [PMID: 34240972 DOI: 10.1063/5.0052479] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have investigated the structure and phase behavior of biocompatible, aqueous deep eutectic solvents by combining choline acetate, hydrogen aspartate, and aspartate amino acid salts with water as the sole molecular hydrogen bond donor. Using contrast-variation neutron diffraction, interpreted via computational modeling, we show how the interplay between anion structure and water content affects the hydrogen bond network structure in the liquid, which, in turn, influences the eutectic composition and temperature. These mixtures expand the current range choline amino acid ionic liquids under investigation for biomass processing applications to include higher melting point salts and also explain how the ionic liquids retain their desirable properties in aqueous solution.
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Affiliation(s)
- Shurui Miao
- School of Chemistry and Sydney Nano Institute, The University of Sydney, NSW 2006, Australia
| | - Haihui Joy Jiang
- School of Chemistry and Sydney Nano Institute, The University of Sydney, NSW 2006, Australia
| | - Silvia Imberti
- STFC, ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, WA 6009, Australia
| | - Gregory Warr
- School of Chemistry and Sydney Nano Institute, The University of Sydney, NSW 2006, Australia
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18
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Bodo E. Modelling biocompatible ionic liquids based on organic acids and amino acids: challenges for computational models and future perspectives. Org Biomol Chem 2021; 19:4002-4013. [PMID: 33978045 DOI: 10.1039/d1ob00011j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this short review I shall highlight the basic principle and the difficulties that arise in attempting the computational modeling of seemingly simple systems which hide an unexpected complexity. Biocompatible ionic liquids which are based on the coupling of organic or amino acid anions with metabolic cations such as cholinium are the target of this review. These substances have been the subject of intense research activities in the last few years and have attracted the attention of computational chemists. I shall show that the computational description of these substances is far from trivial and requires the use of sophisticated techniques in order to account for a surprisingly rich chemistry that is due to several phenomena such as polarization, charge transfer, proton transfer equilibria and tautomerization reactions.
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Affiliation(s)
- Enrico Bodo
- Chemistry Department, University of Rome "La Sapienza", P. A. Moro 5, 00185 Rome, Italy.
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Dhattarwal HS, Kashyap HK. Unique and generic structural features of cholinium amino acid-based biocompatible ionic liquids. Phys Chem Chem Phys 2021; 23:10662-10669. [PMID: 33908525 DOI: 10.1039/d1cp00937k] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cholinium amino acid-based (Ch-AA) biocompatible ionic liquids (bio-ILs) are synthesized from renewable components and are efficiently used for biomass processing. However, their microscopic structural features that lead to their application as biomass solvents remain undetermined. Herein, we use atomistic simulations to investigate the structures of six different Ch-AA bio-ILs up to the nanometer length scale and demonstrate that, depending on the anion side chain structure, the respective IL exhibits structural ordering at different length scales. All the six Ch-AA bio-ILs investigated here show a generic feature of having a strong hydrogen bonding network between the hydroxyl group of the cholinium cation and the carboxyl group of the amino acid anions. We illustrate that each of these bio-ILs also displays a unique feature. Distinctive intermediate range structural ordering leads to heterogeneity in methioninate- and phenylalaninate-based ILs caused by the anion side chain segregation. Intermediate range ordering is not observed in glutaminate- and glutamate-based ILs because significant anion side chain and backbone interactions hinder the formation of side chain clusters. Interestingly, for the cysteinate-based IL, the side chains do not interact with the backbones and the intermediate range ordering is not observed because of a shorter anionic side chain.
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Affiliation(s)
- Harender S Dhattarwal
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
| | - Hemant K Kashyap
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India.
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Le Donne A, Bodo E. Cholinium amino acid-based ionic liquids. Biophys Rev 2021; 13:147-160. [PMID: 33747249 PMCID: PMC7930144 DOI: 10.1007/s12551-021-00782-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/05/2021] [Indexed: 12/12/2022] Open
Abstract
Boosted by the simplicity of their synthesis and low toxicity, cholinium and amino acid-based ionic liquids have attracted the attention of researchers in many different fields ranging from computational chemistry to electrochemistry and medicine. Among the uncountable IL variations, these substances occupy a space on their own due to their exceptional biocompatibility that stems from being entirely made by metabolic molecular components. These substances have undergone a rather intensive research activity because of the possibility of using them as greener replacements for traditional ionic liquids. We present here a short review in the attempt to provide a compendium of the state-of-the-art scientific research about this special class of ionic liquids based on the combination of amino acid anions and cholinium cations.
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Affiliation(s)
- Andrea Le Donne
- Chemistry Department, University of Rome "La Sapienza", Piazzale A. Moro 5, 00185 Rome, Italy
| | - Enrico Bodo
- Chemistry Department, University of Rome "La Sapienza", Piazzale A. Moro 5, 00185 Rome, Italy
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Miao S, Wood J, Jiang HJ, Imberti S, Atkin R, Warr G. Unusual origin of choline phenylalaninate ionic liquid nanostructure. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.114327] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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22
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Shmool TA, Martin LK, Clarke CJ, Bui-Le L, Polizzi KM, Hallett JP. Exploring conformational preferences of proteins: ionic liquid effects on the energy landscape of avidin. Chem Sci 2020; 12:196-209. [PMID: 34163590 PMCID: PMC8178808 DOI: 10.1039/d0sc04991c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In this work we experimentally investigate solvent and temperature induced conformational transitions of proteins and examine the role of ion–protein interactions in determining the conformational preferences of avidin, a homotetrameric glycoprotein, in choline-based ionic liquid (IL) solutions. Avidin was modified by surface cationisation and the addition of anionic surfactants, and the structural, thermal, and conformational stabilities of native and modified avidin were examined using dynamic light scattering, differential scanning calorimetry, and thermogravimetric analysis experiments. The protein-surfactant nanoconjugates showed higher thermostability behaviour compared to unmodified avidin, demonstrating distinct conformational ensembles. Small-angle X-ray scattering data showed that with increasing IL concentration, avidin became more compact, interpreted in the context of molecular confinement. To experimentally determine the detailed effects of IL on the energy landscape of avidin, differential scanning fluorimetry and variable temperature circular dichroism spectroscopy were performed. We show that different IL solutions can influence avidin conformation and thermal stability, and we provide insight into the effects of ILs on the folding pathways and thermodynamics of proteins. To further study the effects of ILs on avidin binding and correlate thermostability with conformational heterogeneity, we conducted a binding study. We found the ILs examined inhibited ligand binding in native avidin while enhancing binding in the modified protein, indicating ILs can influence the conformational stability of the distinct proteins differently. Significantly, this work presents a systematic strategy to explore protein conformational space and experimentally detect and characterise ‘invisible’ rare conformations using ILs. Revealing solvent and temperature induced conformational transitions of proteins and the role of ion–protein interactions in determining the conformational preferences of avidin in ionic liquids.![]()
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Affiliation(s)
- Talia A Shmool
- Department of Chemical Engineering, Imperial College London London SW7 2AZ UK +44 (0)20 7594 5388
| | - Laura K Martin
- Department of Chemical Engineering, Imperial College London London SW7 2AZ UK +44 (0)20 7594 5388.,Imperial College Centre for Synthetic Biology, Imperial College London London SW7 2AZ UK
| | - Coby J Clarke
- Department of Chemical Engineering, Imperial College London London SW7 2AZ UK +44 (0)20 7594 5388
| | - Liem Bui-Le
- Department of Chemical Engineering, Imperial College London London SW7 2AZ UK +44 (0)20 7594 5388
| | - Karen M Polizzi
- Department of Chemical Engineering, Imperial College London London SW7 2AZ UK +44 (0)20 7594 5388.,Imperial College Centre for Synthetic Biology, Imperial College London London SW7 2AZ UK
| | - Jason P Hallett
- Department of Chemical Engineering, Imperial College London London SW7 2AZ UK +44 (0)20 7594 5388
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