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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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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: 3] [Impact Index Per Article: 3.0] [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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3
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Busch J, Kotwica D, Al Sheakh L, Headen T, Youngs TGA, Paschek D, Ludwig R. Quantification and Distribution of Three Types of Hydrogen Bonds in Mixtures of an Ionic Liquid with the Hydrogen-Bond-Accepting Molecular Solvent DMSO Explored by Neutron Diffraction and Molecular Dynamics Simulations. J Phys Chem Lett 2023; 14:2684-2691. [PMID: 36892277 DOI: 10.1021/acs.jpclett.3c00018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The concept of hydrogen bonding is celebrating its 100th birthday. Hydrogen bonds (H-bonds) play a key role in the structure and function of biological molecules, the strength of materials, and molecular binding. Herein, we study H-bonding in mixtures of a hydroxyl-functionalized ionic liquid with the neutral, H-bond-accepting molecular liquid dimethylsulfoxide (DMSO) using neutron diffraction experiments and molecular dynamics simulations. We report the geometry, strength, and distribution of three different types of H-bond OH···O, formed between the hydroxyl group of the cation and either the oxygen atom of another cation, the counteranion, or the neutral molecule. Such a variety of different strengths and distributions of H-bonds in one single mixture could hold the promise of providing solvents with potential applications in H-bond-related chemistry, for example, to alter the natural selectivity patterns of catalytic reactions or the conformation of catalysts.
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Affiliation(s)
- Johanna Busch
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - David Kotwica
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - Loai Al Sheakh
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - Thomas Headen
- ISIS Faculty, STFC, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Tristan G A Youngs
- ISIS Faculty, STFC, Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Dietmar Paschek
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
| | - Ralf Ludwig
- Institut für Chemie, Abteilung Physikalische und Theoretische Chemie, Universität Rostock, Albert-Einstein-Str. 27, 18059 Rostock, Germany
- Department LL&M, Universität Rostock, Albert-Einstein-Str. 25, 18059 Rostock, Germany
- Leibniz-Institut für Katalyse an der Universität Rostock e.V., Albert-Einstein-Str. 29a, 18059 Rostock, Germany
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Hydration of the Neurotransmitter γ-Aminobutyric Acid and its Isomer α-Aminobutyric Acid. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2023.121363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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5
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Li E, Li Y, Liu S, Yao P. Choline amino acid ionic liquids as green corrosion inhibitors of mild steel in acidic medium. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.130541] [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]
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6
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Russo S, Bodo E. A polarisable force field for bio-compatible ionic liquids based on amino acids anions. MOLECULAR SIMULATION 2022. [DOI: 10.1080/08927022.2022.2113810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Affiliation(s)
- Stefano Russo
- Department of Chemistry, University of Rome “La Sapienza”, Rome, Italy
| | - Enrico Bodo
- Department of Chemistry, University of Rome “La Sapienza”, Rome, Italy
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Site Density Functional Theory and Structural Bioinformatics Analysis of the SARS-CoV Spike Protein and hACE2 Complex. Molecules 2022; 27:molecules27030799. [PMID: 35164065 PMCID: PMC8839245 DOI: 10.3390/molecules27030799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 12/02/2022] Open
Abstract
The entry of the SARS-CoV-2, a causative agent of COVID-19, into human host cells is mediated by the SARS-CoV-2 spike (S) glycoprotein, which critically depends on the formation of complexes involving the spike protein receptor-binding domain (RBD) and the human cellular membrane receptor angiotensin-converting enzyme 2 (hACE2). Using classical site density functional theory (SDFT) and structural bioinformatics methods, we investigate binding and conformational properties of these complexes and study the overlooked role of water-mediated interactions. Analysis of the three-dimensional reference interaction site model (3DRISM) of SDFT indicates that water mediated interactions in the form of additional water bridges strongly increases the binding between SARS-CoV-2 spike protein and hACE2 compared to SARS-CoV-1-hACE2 complex. By analyzing structures of SARS-CoV-2 and SARS-CoV-1, we find that the homotrimer SARS-CoV-2 S receptor-binding domain (RBD) has expanded in size, indicating large conformational change relative to SARS-CoV-1 S protein. Protomer with the up-conformational form of RBD, which binds with hACE2, exhibits stronger intermolecular interactions at the RBD-ACE2 interface, with differential distributions and the inclusion of specific H-bonds in the CoV-2 complex. Further interface analysis has shown that interfacial water promotes and stabilizes the formation of CoV-2/hACE2 complex. This interaction causes a significant structural rigidification of the spike protein, favoring proteolytic processing of the S protein for the fusion of the viral and cellular membrane. Moreover, conformational dynamics simulations of RBD motions in SARS-CoV-2 and SARS-CoV-1 point to the role in modification of the RBD dynamics and their impact on infectivity.
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Friesen S, Fedotova MV, Kruchinin SE, Bešter-Rogač M, Podlipnik Č, Buchner R. Hydration and counterion binding of aqueous acetylcholine chloride and carbamoylcholine chloride. Phys Chem Chem Phys 2021; 23:25086-25096. [PMID: 34747952 DOI: 10.1039/d1cp03543f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The hydration and Cl- ion binding of the neurot†ransmitter acetylcholine (ACh+) and its synthetic analogue, carbamoylcholine (CCh+), were studied by combining dilute-solution conductivity measurements with dielectric relaxation spectroscopy and statistical mechanics calculations at 1D-RISM and 3D-RISM level. Chloride ion binding was found to be weak but not negligible. From the ∼30 water molecules coordinating ACh and CCh+ only ∼1/3 is affected in its rotational dynamics by the cation, with the majority - situated close to the hydrophobic moieties - only retarded by a factor of ∼2.5. At vanishing solute concentration cations and the ∼3-4 H2O molecules hydrogen bonding to the CO group of the solute exhibit similar rotational dynamics but increasing concentration and temperature markedly dehydrates ACh+ and CCh+.
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Affiliation(s)
- Sergej Friesen
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany.
| | - Marina V Fedotova
- G. A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Kademicheskaya st. 1, 153045 Ivanovo, Russian Federation.
| | - Sergey E Kruchinin
- G. A. Krestov Institute of Solution Chemistry, Russian Academy of Sciences, Kademicheskaya st. 1, 153045 Ivanovo, Russian Federation.
| | - Marija Bešter-Rogač
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.
| | - Črtomir Podlipnik
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.
| | - Richard Buchner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany.
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Kruchinin SE, Fedotova MV. Ion Pairing of the Neurotransmitters Acetylcholine and Glutamate in Aqueous Solutions. J Phys Chem B 2021; 125:11219-11231. [PMID: 34597044 DOI: 10.1021/acs.jpcb.1c05117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neurotransmitters (NTs) play an important role in neural communication, regulating a variety of functions such as motivation, learning, memory, and muscle contraction. Their intermolecular interactions in biological media are an important factor affecting their biological activity. However, the available information on the features of these interactions is scarce and contradictory, especially, in an estimation of possible ion binding. In this paper, we present the results of a study for two well-known NTs, acetylcholine (ACh) and glutamate (Glu), with relation to the NT-inorganic ion and the NT-NT binding in a water environment. The features of NT pairing are investigated in aqueous AChCl and NaGlu solutions over a wide concentration range using the integral equation method in 1D- and 3D- reference interaction site model (RISM) approaches. The data for ACh are given for its two bioactive TG (trans, gauche) and TT (trans, trans) conformers. As was found, for both NTs, the results indicate the NT-inorganic counterion contact pair to be the predominant associate type in the concentrated solutions. In this case, the counterions occupy the vacated "water" space in the hydration shell of the onium moiety (ACh) or carboxylate groups (Glu). For ACh, the "unfolded" TT conformer demonstrates a slightly greater possibility for counterion pairing in comparison with the "folded" TG conformer. For Glu, the probability of its binding with a counterion is slightly stronger for the "side-chain" carboxylate group than for the "backbone" group. The obtained results also revealed an insignificant probability of Glu--Glu- pairing. Namely, the RISM data indicate Glu--Glu- binding by NH3+-COO- interactions. A link between the ion binding of NTs and their biological activity is discussed. This contribution adds new knowledge to our understanding of the interactions between the NTs and their molecular environment, providing further insights into the behavior of these compounds in biological media.
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Affiliation(s)
- Sergey E Kruchinin
- G.A. Krestov Institute of Solution Chemistry, the Russian Academy of Sciences, Akademicheskaya Street 1, Ivanovo 153045, Russia
| | - Marina V Fedotova
- G.A. Krestov Institute of Solution Chemistry, the Russian Academy of Sciences, Akademicheskaya Street 1, Ivanovo 153045, Russia
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Niesyto K, Łyżniak W, Skonieczna M, Neugebauer D. Biological In Vitro Evaluation of PIL Graft Conjugates: Cytotoxicity Characteristics. Int J Mol Sci 2021; 22:7741. [PMID: 34299358 PMCID: PMC8306113 DOI: 10.3390/ijms22147741] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/16/2021] [Accepted: 07/17/2021] [Indexed: 11/19/2022] Open
Abstract
In vitro cytotoxicity of polymer-carriers, which in the side chains contain the cholinum ionic liquid units with chloride (Cl) or pharmaceutical anions dedicated for antituberculosis therapy, i.e., p-aminosalicylate (PAS) and clavulanate (CLV), was investigated. The carriers and drug conjugates were examined, in the concentration range of 3.125-100 μg/mL, against human bronchial epithelial cells (BEAS-2B) and adenocarcinomic human alveolar basal epithelial cells (A549) as an experimental model cancer cell line possibly coexisting in tuberculosis. The cytotoxicity was evaluated by MTT test and confluency index, as well as by the cytometric analyses, including Annexin-V FITC apoptosis assay. The polymer systems showed supporting activity towards the normal cells and no tumor progress, especially at the highest concentration (100 μg/mL). The analysis of cell death did not show meaningful changes in the case of the BEAS-2B, whereas in the A549 cell line, the cytostatic activity was observed, especially for the drug-free carriers, causing death in up to 80% of cells. This can be regulated by the polymer structure, including the content of cationic units, side-chain length and density, as well as the type and content of pharmaceutical anions. The results of MTT tests, confluency, as well as cytometric analyses, distinguished the polymer systems with Cl/PAS/CLV containing 26% of grafting degree and 43% of ionic units or 46% of grafting degree and 18% of ionic units as the optimal systems.
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Affiliation(s)
- Katarzyna Niesyto
- Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, 44-100 Gliwice, Poland
| | - Wiktoria Łyżniak
- Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, 44-100 Gliwice, Poland
| | - Magdalena Skonieczna
- Department of Systems Biology and Engineering, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland
- Biotechnology Centre, Silesian University of Technology, Krzywoustego 8, 44-100 Gliwice, Poland
| | - Dorota Neugebauer
- Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, 44-100 Gliwice, Poland
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Yadav R, Kahlon NK, Kumar S, Devunuri N, Venkatesu P. Biophysical study on the phase transition behaviour of biocompatible thermoresponsive polymer influenced by tryptophan-based amino acid ionic liquids. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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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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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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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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Khorrami F, Kowsari MH. Tracing Local Nanostructure of the Aqueous Solutions of the Biocompatible [Cho][Gly] Ionic Liquid: Importance of Hydrogen Bond Attraction between Like-Charged Ions. J Phys Chem B 2020; 124:3770-3783. [PMID: 32275831 DOI: 10.1021/acs.jpcb.0c01796] [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
The neat and aqueous solutions of the cholinium glycinate ionic liquid (IL), [Cho][Gly], at different water mole fractions, xws, are studied by molecular dynamics simulations. The changes in the local nanostructure of systems with composition have been determined by calculation of various structural distribution functions. Hydrogen bond (H-bond) attractions determine the major relative orientations of the oppositely and like charged nearest neighbors. The cation-anion H-bonds mainly form between the hydrogen of the hydroxyl or methyl groups of the cation and the carboxylate oxygen of the anion. A preferred (antiparallel) arrangement between adjacent [Cho]+ cations is due to the effective H-bond between the hydroxyl oxygen and the methyl hydrogen sites that promotes the like-charge cluster formation. Adding water decreases the occurrence probability of the [Cho]+···[Gly]-···[Cho]+ bridge structure in the aqueous solutions due to the formation of the [Gly]-···HOH···[Gly]- structure via H-bonding. Observed density trend versus xw is interpreted based on an interstice model and investigating the water cluster size distribution. Finally, the effect of xw on the infrared (IR) vibrational spectra were studied and blue and red shifts were observed for the stretching and bending vibrational modes of the hydroxyl group of [Cho]+, respectively. Current findings will improve the efficient engineering design and task-specific applications of aqueous solutions of bio-ILs consist of [Cho]+ and amino acid anions.
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Affiliation(s)
- Farzad Khorrami
- Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
| | - Mohammad H Kowsari
- Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.,Center for Research in Climate Change and Global Warming (CRCC), Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran
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Abstract
Schematic representation of the multipolar molecule surrounded by salt ions in a dielectric solvent medium.
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Affiliation(s)
- Yury A. Budkov
- School of Applied Mathematics
- National Research University Higher School of Economics
- 123458 Moscow
- Russia
- G. A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences
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