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Hsieh AY, Haines RS, Harper JB. Effects of Ionic Liquids on the Nucleofugality of Bromide. J Org Chem 2024; 89:6247-6256. [PMID: 38655582 DOI: 10.1021/acs.joc.4c00249] [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
The nucleofugality of bromide was measured in solvent mixtures containing ionic liquids. The solvolysis rate constants of the bromides of well-defined electrofuges were determined in mixtures containing different proportions of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide in ethanol. Temperature-dependent kinetic studies allowed an explanation of the observed solvent effects in different mixtures in terms of interactions in solution. Using the solvolysis data, the nucleofugality of bromide in these systems was determined. Likewise, nucleofugality data for bromide were determined in mixtures containing high proportions of seven further ionic liquids. These data allowed quantification of the effects of both varying the amount of ionic liquid and the nature of ionic liquid components on the nucleofugality of bromide. Importantly, ionic liquid mixtures were shown to affect the nucleofugality in a manner similar to chloride, providing a method for predicting the effects of ionic liquids on other electrofuges. Further, the ionic liquids were shown to move the transition state earlier along the reaction coordinate, meaning that there is less charge development in the transition state.
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Affiliation(s)
- Andrew Y Hsieh
- School of Chemistry, University of New South Wales, UNSW, Sydney, NSW 2052, Australia
| | - Ronald S Haines
- School of Chemistry, University of New South Wales, UNSW, Sydney, NSW 2052, Australia
| | - Jason B Harper
- School of Chemistry, University of New South Wales, UNSW, Sydney, NSW 2052, Australia
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2
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Hsieh AY, Haines RS, Harper JB. The effects of ionic liquids on the ethanolysis of a chloroacenaphthene. Evaluation of the effectiveness of nucleofugality data to predict reaction outcome. RSC Adv 2023; 13:21036-21043. [PMID: 37448642 PMCID: PMC10336772 DOI: 10.1039/d3ra04302a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/15/2023] Open
Abstract
The reaction of a chlorobenzene in mixtures containing ethanol and eight different ionic liquids was investigated in order to understand the effects of varying proportions and constituent ions of an ionic liquid on the rate constant of the process. The results were found to be generally consistent with previously studied reactions of the same type, with small proportions of an ionic liquid resulting in a rate constant increase compared to ethanol and large proportions causing a rate constant decrease. Temperature dependent kinetic studies were used to interpret the changes in reaction outcome, particularly noting an entropic cost on moving to high proportions of ionic liquid, consistent with organisation of solvent around the transition state. While attempts to use empirical solvent parameters to correlate outcome with the ionic liquid used were unsuccessful, use of recently acquired nucleofugality data for chloride and estimations for the electrofuge allowed for excellent prediction of the effects of ionic liquids, with rate constants quantitatively predicted in systems containing both different proportions of ionic liquid (mean absolute error (MAE) log(k1) = 0.11) and different ionic liquids (MAE log(k1) = 0.33). Importantly, this demonstrates the ready application of these quantitative reactivity parameters.
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Affiliation(s)
- Andrew Y Hsieh
- School of Chemistry, University of New South Wales UNSW Sydney NSW 2052 Australia +61 2 9385 6141 +61 2 9385 4692
| | - Ronald S Haines
- School of Chemistry, University of New South Wales UNSW Sydney NSW 2052 Australia +61 2 9385 6141 +61 2 9385 4692
| | - Jason B Harper
- School of Chemistry, University of New South Wales UNSW Sydney NSW 2052 Australia +61 2 9385 6141 +61 2 9385 4692
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3
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Matthewman EL, Kapila B, Grant ML, Weber CC. The amphiphilic nanostructure of ionic liquids affects the dehydration of alcohols. Chem Commun (Camb) 2022; 58:13572-13575. [PMID: 36412193 DOI: 10.1039/d2cc04854j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effect of the amphiphilic nanostructure of ionic liquids on the dehydration of secondary alcohols to alkenes has been investigated. The influence of these nanostructures was inverted when an acid catalyst was added to the reaction. This phenomenon was ascribed to a balance between ion-solute interactions and the formation of solute-catalyst hydrogen bonds, highlighting the complex interplay between interactions and reaction outcomes in these nanostructured solvent systems.
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Affiliation(s)
- Emma L Matthewman
- School of Chemical Sciences, The University of Auckland, Auckland, New Zealand. .,MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
| | - Bhavana Kapila
- School of Science, Auckland University of Technology, Auckland, New Zealand
| | - Mason L Grant
- School of Chemical Sciences, The University of Auckland, Auckland, New Zealand. .,MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
| | - Cameron C Weber
- School of Chemical Sciences, The University of Auckland, Auckland, New Zealand. .,MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
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4
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Coney MD, Morris DC, Gilbert A, Prescott SW, Haines RS, Harper JB. Effects of Ionic Liquids on the Nucleofugality of Chloride. J Org Chem 2021; 87:1767-1779. [PMID: 34756050 DOI: 10.1021/acs.joc.1c02043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nucleofugality of chloride has been measured in solvent mixtures containing ionic liquids for the first time, allowing reactivity in these solvents to be put in context with molecular solvents. Using well-described electrofuges, solvolysis rate constants were determined in mixtures containing different proportions of ethanol and the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide; the different solvent effects observed as the mixture changed could be explained using interactions of the ionic liquid with species along the reaction coordinate, determined using temperature dependent kinetic studies. The solvolysis data allowed determination of the nucleofugality of chloride in these mixtures, which varied with the proportion of salt in the reaction mixture, demonstrating quantitatively the importance of the amount of ionic liquid in the reaction mixture in determining reaction outcome. Nucleofugality data for chloride were determined in seven further ionic liquids, with the reactivity shown to vary over more than an order of magnitude. This outcome illustrates that the components of the ionic liquid are critical in determining reaction outcome. Overall, this work quantitatively extends the understanding of solvent effects in ionic liquids and demonstrates the potential for such information to be used to rationally select an ionic liquid to control reaction outcome.
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5
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Gilbert A, Haines RS, Harper JB. The effects of using an ionic liquid as a solvent for a reaction that proceeds through a phenonium ion. J PHYS ORG CHEM 2021. [DOI: 10.1002/poc.4217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Alyssa Gilbert
- School of Chemistry University of New South Wales, UNSW Sydney Sydney New South Wales Australia
| | - Ronald S. Haines
- School of Chemistry University of New South Wales, UNSW Sydney Sydney New South Wales Australia
| | - Jason B. Harper
- School of Chemistry University of New South Wales, UNSW Sydney Sydney New South Wales Australia
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6
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Kochly ED, Deh-Lee AM, Lemon NJ, Rath J, Escobar-Meza A. The effect of ionic liquid cosolvents on a unimolecular solvolysis reaction in 2,2,2-trifluoroethanol. RESULTS IN CHEMISTRY 2021. [DOI: 10.1016/j.rechem.2021.100213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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7
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Kahlon NK, Weber CC. Micellar Catalysis and Reactivity in Nanostructured Ionic Liquids: Two Sides of the Same Coin? Aust J Chem 2021. [DOI: 10.1071/ch21109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Luo W, Mao C, Ji P, Wu JY, Yang JD, Cheng JP. Counterintuitive solvation effect of ionic-liquid/DMSO solvents on acidic C-H dissociation and insight into respective solvation. Chem Sci 2020; 11:3365-3370. [PMID: 34122844 PMCID: PMC8152793 DOI: 10.1039/c9sc06341b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
How would acidic bond dissociation be affected by adding a small quantity of a weakly polar ionic liquid IL (the "apparent" or "measured" dielectric constant ε of the IL is around 10-15) into a strongly polar molecular solvent (e.g., ε of DMSO: 46.5), or vice versa? The answer is blurred, because no previous investigation was reported in this regard. Toward this, we, taking various IL/DMSO mixtures as representatives, have thoroughly investigated the effects of the respective solvent in ionic-molecular binary systems on self-dissociation of C-H acid phenylmalononitrile PhCH(CN)2 via pK a determination. As disclosed, in this category of binary media, (1) no linear correspondence exists between pK a and molar fractions of the respective solvent components; (2) only ∼1-2 mol% of weakly polar ILs in strongly polar DMSO make C-H bonds even more dissociative than in neat DMSO; (3) a small fraction of DMSO in ILs (<10 mol%) can dramatically ease acidic C-H-dissociation; and (4) while the DMSO fraction further increases, its acidifying effect becomes much attenuated. These findings, though maybe counterintuitive, have been rationalized on the basis of the precise pK a measurement of this work in relation to the respective roles of each solvent component in solvation.
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Affiliation(s)
- Wenzhi Luo
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University Beijing 100084 China
| | - Chong Mao
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University Beijing 100084 China
| | - Pengju Ji
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University Beijing 100084 China
| | - Jun-Yan Wu
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University Beijing 100084 China
| | - Jin-Dong Yang
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University Beijing 100084 China
| | - Jin-Pei Cheng
- Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University Beijing 100084 China .,State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University Tianjin 300071 China
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9
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Schaffarczyk McHale KS, Haines RS, Harper JB. Ionic Liquids as Solvents for S N 2 Processes. Demonstration of the Complex Interplay of Interactions Resulting in the Observed Solvent Effects. Chempluschem 2020; 83:1162-1168. [PMID: 31950706 DOI: 10.1002/cplu.201800510] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 11/03/2018] [Indexed: 11/11/2022]
Abstract
Bimolecular nucleophilic substitution reactions between triphenylphosphine and benzylic electrophiles have been examined in an ionic liquid to probe interactions with species along the reaction coordinate. Trends in the rate constant were found on both varying the leaving group and the electronic nature of the aromatic ring. In all the cases considered, interactions between the components of the ionic liquid and the transition state were shown to be more significant in determining reaction outcome than previously observed for this class of reaction. This demonstrates the importance of considering interactions of the ionic liquid components with all species along the reaction coordinate when investigating the origin of ionic liquid solvent effects, along with how such effects might be exploited.
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Affiliation(s)
| | - Ronald S Haines
- School of Chemistry, University of New South Wales UNSW, Sydney, NSW 2052, Australia
| | - Jason B Harper
- School of Chemistry, University of New South Wales UNSW, Sydney, NSW 2052, Australia
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10
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Schaffarczyk McHale KS, Haines RS, Harper JB. Investigating Variation of the Pnicogen Nucleophilic Heteroatom on Ionic Liquid Solvent Effects in Bimolecular Nucleophilic Substitution Processes. Chempluschem 2020; 84:534-539. [PMID: 31943899 DOI: 10.1002/cplu.201900188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/03/2019] [Indexed: 01/22/2023]
Abstract
A series of nucleophiles containing Group 15 nucleophilic heteroatoms has been used to expand and develop the current understanding of ionic liquid solvent effects on bimolecular nucleophilic substitution processes. It was found that when using arsenic-, antimony- and bismuth-based nucleophiles, rate constant enhancement was observed for all solvent compositions containing ionic liquids. This rate constant enhancement was driven by ionic liquid/transition state interactions, which contrasts with previous studies on earlier Group 15 nucleophiles. This study provides a holistic understanding and augments the predictive framework for the effects of ionic liquids on bimolecular nucleophilic substitution processes, with the potential for these periodic trends to be broadly applied.
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Affiliation(s)
| | - Ronald S Haines
- School of Chemistry, University of New South Wales, UNSW Sydney, NSW 2052, Australia
| | - Jason B Harper
- School of Chemistry, University of New South Wales, UNSW Sydney, NSW 2052, Australia
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11
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Schindl A, Hawker RR, Schaffarczyk McHale KS, Liu KTC, Morris DC, Hsieh AY, Gilbert A, Prescott SW, Haines RS, Croft AK, Harper JB, Jäger CM. Controlling the outcome of S N2 reactions in ionic liquids: from rational data set design to predictive linear regression models. Phys Chem Chem Phys 2020; 22:23009-23018. [PMID: 33043942 DOI: 10.1039/d0cp04224b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Rate constants for a bimolecular nucleophilic substitution (SN2) process in a range of ionic liquids are correlated with calculated parameters associated with the charge localisation on the cation of the ionic liquid (including the molecular electrostatic potential). Simple linear regression models proved effective, though the interdependency of the descriptors needs to be taken into account when considering generality. A series of ionic liquids were then prepared and evaluated as solvents for the same process; this data set was rationally chosen to incorporate homologous series (to evaluate systematic variation) and functionalities not available in the original data set. These new data were used to evaluate and refine the original models, which were expanded to include simple artificial neural networks. Along with showing the importance of an appropriate data set and the perils of overfitting, the work demonstrates that such models can be used to reliably predict ionic liquid solvent effects on an organic process, within the limits of the data set.
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Affiliation(s)
- Alexandra Schindl
- Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Rebecca R Hawker
- School of Chemistry, University of New South Wales, UNSW Sydney, 2052, Australia.
| | | | - Kenny T-C Liu
- School of Chemistry, University of New South Wales, UNSW Sydney, 2052, Australia.
| | - Daniel C Morris
- School of Chemistry, University of New South Wales, UNSW Sydney, 2052, Australia. and School of Chemical Engineering, University of New South Wales, UNSW Sydney, 2052, Australia
| | - Andrew Y Hsieh
- School of Chemistry, University of New South Wales, UNSW Sydney, 2052, Australia.
| | - Alyssa Gilbert
- School of Chemistry, University of New South Wales, UNSW Sydney, 2052, Australia.
| | - Stuart W Prescott
- School of Chemical Engineering, University of New South Wales, UNSW Sydney, 2052, Australia
| | - Ronald S Haines
- School of Chemistry, University of New South Wales, UNSW Sydney, 2052, Australia.
| | - Anna K Croft
- Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Jason B Harper
- School of Chemistry, University of New South Wales, UNSW Sydney, 2052, Australia.
| | - Christof M Jäger
- Department of Chemical and Environmental Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
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12
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Gilbert A, Haines RS, Harper JB. Controlling the reactions of 1-bromogalactose acetate in methanol using ionic liquids as co-solvents. Org Biomol Chem 2020; 18:5442-5452. [PMID: 32638805 DOI: 10.1039/d0ob01198c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactions of an acetobromogalactose in mixtures of methanol and one of seven different ionic liquids with varying constituent ions were studied. In general, small amounts of ionic liquid in the reaction mixture led to increases in the rate constant compared to methanol, whilst large amounts of ionic liquid led to decreases in the rate constant; this outcome differs significantly from previous reactions proceeding through this mechansim. Temperature dependent kinetic studies indicated that the dominant interaction driving these changes was between the ionic liquid and the transition state of the process. Through considering solvent parameters of ionic liquids, a relationship was found between the changes in the rate constant and both the hydrogen bond accepting ability and polarisability of the solvent, indicating that the interactions affecting reaction outcome are both specific and non-specific in nature; once more, these interactions were different to those observed in previous similar reactions. By changing the amount of ionic liquid in the reaction mixture, additional products not seen in the molecular solvent case were observed, the ratios of which are dependent on the anion of the ionic liquid and the proportion of ionic liquid in the reaction mixture. This demonstrates the importance of considering solvent effects on both the rate and product determining steps and the potential application of such changes is discussed.
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Affiliation(s)
- Alyssa Gilbert
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Ronald S Haines
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Jason B Harper
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
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13
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Gilbert A, Bucher G, Haines RS, Harper JB. Correlating ionic liquid solvent effects with solvent parameters for a reaction that proceeds through a xanthylium intermediate. Org Biomol Chem 2019; 17:9336-9342. [PMID: 31612896 DOI: 10.1039/c9ob01807g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A unimolecular nucleophilic substitution reaction that proceeds through a xanthylium carbocation was studied in seven ionic liquid solvents. It was found that the general trend in the rate constant with changing proportion of ionic liquid in the reaction mixture was different to that seen for other unimolecular processes, with the rate constant increasing as more ionic liquid was added to the reaction mixture. A significant correlation was found between the natural logarithm of the rate constant and a combination of the Kamlet-Taft solvent parameters. This relationship indicated that the principal interaction involved hydrogen bonding between the ionic liquid and some species along the reaction coordinate. Further, this correlation enables prediction of the effects that other ionic liquids will have on this, and other, reactions that proceed through a similar intermediate.
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Affiliation(s)
- Alyssa Gilbert
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
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14
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Schindl A, Hagen ML, Muzammal S, Gunasekera HAD, Croft AK. Proteins in Ionic Liquids: Reactions, Applications, and Futures. Front Chem 2019; 7:347. [PMID: 31179267 PMCID: PMC6543490 DOI: 10.3389/fchem.2019.00347] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 04/26/2019] [Indexed: 01/01/2023] Open
Abstract
Biopolymer processing and handling is greatly facilitated by the use of ionic liquids, given the increased solubility, and in some cases, structural stability imparted to these molecules. Focussing on proteins, we highlight here not just the key drivers behind protein-ionic liquid interactions that facilitate these functionalities, but address relevant current and potential applications of protein-ionic liquid interactions, including areas of future interest.
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Affiliation(s)
- Alexandra Schindl
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
- Faculty of Medicine & Health Sciences, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
- Faculty of Science, School of Pharmacy, University of Nottingham, Nottingham, United Kingdom
| | - Matthew L. Hagen
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
- Centre for Additive Manufacturing, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
| | - Shafaq Muzammal
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
| | - Henadira A. D. Gunasekera
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
- Centre for Additive Manufacturing, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
| | - Anna K. Croft
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom
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15
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Gilbert A, Haines RS, Harper JB. Understanding the effects of ionic liquids on a unimolecular substitution process: correlating solvent parameters with reaction outcome. Org Biomol Chem 2019; 17:675-682. [DOI: 10.1039/c8ob02460j] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The polarisability of an ionic liquid is key in determining the rate constant of a unimolecular substitution process.
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Affiliation(s)
- Alyssa Gilbert
- School of Chemistry
- University of New South Wales
- Sydney
- Australia
| | | | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- Sydney
- Australia
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16
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Keaveney ST, Harper JB, Croft AK. Ion-Reagent Interactions Contributing to Ionic Liquid Solvent Effects on a Condensation Reaction. Chemphyschem 2018; 19:3279-3287. [PMID: 30289579 DOI: 10.1002/cphc.201800695] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Indexed: 11/09/2022]
Abstract
Molecular dynamics simulations of solutions of hexan-1-amine or 4-methoxybenzaldehyde in acetonitrile, an ionic liquid/acetonitrile mixture (χIL =0.2), and a number of different (neat) ionic liquids were performed, to further understand the solvent effects on the condensation reaction of these species. This work indicates that, in the presence of an ionic liquid, the amine group of hexan-1-amine is exclusively solvated by the components of the ionic liquid, and not by acetonitrile, and that the anion interacts with the aldehyde group of 4-methoxybenzaldehyde. These interactions showed little dependence on the proportion of the ionic liquid present. When varying the cation of the ionic liquid there were changes in the cation-amine interaction, and 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide ([Bm2 im][N(CF3 SO2 )2 ]) was found to order more than expected about the amine. This ordering is likely the origin of the large rate constant values determined in [Bm2 im][N(CF3 SO2 )2 ] for this condensation reaction and explains an anomaly seen previously. When changing the anion, changes were seen in the interactions between both the cation and anion with hexan-1-amine, and the anion with 4-methoxybenzaldehyde. The differing magnitude of these interactions likely causes subtle changes in the activation parameters for this condensation reaction, and provides an explanation for the anomalous rate constant values previously determined when varying the anion.
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Affiliation(s)
- Sinead T Keaveney
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
- Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Jason B Harper
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Anna K Croft
- Department of Chemical and Environmental Engineering, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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17
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Hawker RR, Haines RS, Harper JB. Predicting solvent effects in ionic liquids:
E
xtension of a nucleophilic aromatic substitution reaction on a benzene to a pyridine. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3862] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Rebecca R. Hawker
- School of Chemistry University of New South Wales UNSW Sydney Australia
| | - Ronald S. Haines
- School of Chemistry University of New South Wales UNSW Sydney Australia
| | - Jason B. Harper
- School of Chemistry University of New South Wales UNSW Sydney Australia
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18
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Affiliation(s)
- Navjeet Kaur
- Department of Chemistry, Banasthali University, Banasthali, Rajasthan, India
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19
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Eshtaya M, Ejigu A, Stephens G, Walsh DA, Chen GZ, Croft AK. Developing energy efficient lignin biomass processing - towards understanding mediator behaviour in ionic liquids. Faraday Discuss 2018; 190:127-45. [PMID: 27228384 DOI: 10.1039/c5fd00226e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Environmental concerns have brought attention to the requirement for more efficient and renewable processes for chemicals production. Lignin is the second most abundant natural polymer, and might serve as a sustainable resource for manufacturing fuels and aromatic derivatives for the chemicals industry after being depolymerised. In this work, the mediator 2,2'-azino-bis(3-ethylbenthiazoline-6-sulfonic acid) diammonium salt (ABTS), commonly used with enzyme degradation systems, has been evaluated by means of cyclic voltammetry (CV) for enhancing the oxidation of the non-phenolic lignin model compound veratryl alcohol and three types of lignin (organosolv, Kraft and lignosulfonate) in the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate, ([C2mim][C2SO4]). The presence of either veratryl alcohol or organosolv lignin increased the second oxidation peak of ABTS under select conditions, indicating the ABTS-mediated oxidation of these molecules at high potentials in [C2mim][C2SO4]. Furthermore, CV was applied as a quick and efficient way to explore the impact of water in the ABTS-mediated oxidation of both organosolv and lignosulfonate lignin. Higher catalytic efficiencies of ABTS were observed for lignosulfonate solutions either in sodium acetate buffer or when [C2mim][C2SO4] (15 v/v%) was present in the buffer solution, whilst there was no change found in the catalytic efficiency of ABTS in [C2mim][C2SO4]-lignosulfonate mixtures relative to ABTS alone. In contrast, organosolv showed an initial increase in oxidation, followed by a significant decrease on increasing the water content of a [C2mim][C2SO4] solution.
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Affiliation(s)
- Majd Eshtaya
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Andinet Ejigu
- Department of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - Gill Stephens
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Darren A Walsh
- Department of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - George Z Chen
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK. and Department of Chemical and Environmental Engineering, Faculty of Science & Engineering, University of Nottingham Ningbo China, Ningbo 315100, P. R. China
| | - Anna K Croft
- Department of Chemical and Environmental Engineering, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
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20
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Butler BJ, Harper JB. The effect of the structure of the anion of an ionic liquid on the rate of reaction at a phosphorus centre. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3819] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Bradley J. Butler
- School of Chemistry; University of New South Wales, UNSW; Sydney Australia
| | - Jason B. Harper
- School of Chemistry; University of New South Wales, UNSW; Sydney Australia
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Hawker RR, Haines RS, Harper JB. The effect of varying the anion of an ionic liquid on the solvent effects on a nucleophilic aromatic substitution reaction. Org Biomol Chem 2018; 16:3453-3463. [DOI: 10.1039/c8ob00651b] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Variety of ionic liquids with different anions used as solvents for a nucleophilic aromatic substitution reaction.
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Affiliation(s)
| | | | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- Sydney
- Australia
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22
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23
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Keaveney ST, Haines RS, Harper JB. Ionic liquid solvents: the importance of microscopic interactions in predicting organic reaction outcomes. PURE APPL CHEM 2017. [DOI: 10.1515/pac-2016-1008] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractIonic liquids are attractive alternatives to molecular solvents as they have many favourable physical properties and can produce different organic reaction outcomes compared to molecular solvents. Thus far, interactions between the ionic liquid components and specific sites (such as charged centres, lone pairs and π systems) on the reagents and transition state have been identified as affecting reaction outcome; a comprehensive understanding of these interactions is necessary to allow prediction of ionic liquid solvent effects. This manuscript summarises our recent progress in the development of a framework for predicting the effect of an ionic liquid solvent on the outcome of organic processes. There will be a particular focus on the importance of the different interactions between the ionic liquid components and the species along the reaction coordinate that are responsible for the changes in reaction outcome observed in the cases described.
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Affiliation(s)
- Sinead T. Keaveney
- School of Chemistry, University of New South Wales, UNSW Sydney 2052, Australia
| | - Ronald S. Haines
- School of Chemistry, University of New South Wales, UNSW Sydney 2052, Australia
| | - Jason B. Harper
- School of Chemistry, University of New South Wales, UNSW Sydney 2052, Australia
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24
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Keaveney ST, Haines RS, Harper JB. Investigating Solvent Effects of an Ionic Liquid on Pericyclic Reactions through Kinetic Analyses of Simple Rearrangements. Chempluschem 2017; 82:449-457. [DOI: 10.1002/cplu.201600585] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/02/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Sinead T. Keaveney
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
| | - Ronald S. Haines
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
| | - Jason B. Harper
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
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25
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Hawker RR, Wong MJ, Haines RS, Harper JB. Rationalising the effects of ionic liquids on a nucleophilic aromatic substitution reaction. Org Biomol Chem 2017; 15:6433-6440. [DOI: 10.1039/c7ob01476g] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nucleophilic aromatic substitution reaction between 1-fluoro-2,4-dinitrobenzene and ethanol was examined in a series of ionic liquids across a range of mole fractions.
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Affiliation(s)
| | | | | | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- Sydney
- Australia
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26
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Keaveney ST, Greaves TL, Kennedy DF, Harper JB. Understanding the Effect of Solvent Structure on Organic Reaction Outcomes When Using Ionic Liquid/Acetonitrile Mixtures. J Phys Chem B 2016; 120:12687-12699. [PMID: 27973829 DOI: 10.1021/acs.jpcb.6b11090] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The rate constant for the reaction between hexan-1-amine and 4-methoxybenzaldehyde was determined in ionic liquids containing an imidazolium cation. The effect on the rate constant of increasing the length of the alkyl substituent on the cation was examined in a number of ionic liquid/acetonitrile mixtures. In general it was found that there was no significant effect of changing the alkyl substituent on the rate constant of this process, suggesting that any nanodomains in these mixtures do not have a significant effect on the outcome of this process. A series of small-angle X-ray scattering and wide-angle X-ray scattering experiments were performed on mixtures of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Bmim][N(CF3SO2)2]) and acetonitrile; this work indicated that the main structural changes in the mixtures occur by about a 0.2 mole fraction of ionic liquid in the mixture (χIL). This region at which the main changes in the solvent structuring occurs corresponds to the region at which the main changes in the rate constant and activation parameters occur for SN2 and condensation reactions examined previously; this is the first time that such a correlation has been observed. To examine the ordering of the solvent about the nucleophile hexan-1-amine, WAXS experiments were performed on a number of [Bmim][N(CF3SO2)2]/acetonitrile/hexan-1-amine mixtures, where it was found that some of the patterns featured asymmetric peaks as well as additional peaks not observed in the [Bmim][N(CF3SO2)2]/acetonitrile mixtures; this suggests that the addition of hexan-1-amine to the mixture affects the bulk structure of the liquid. The SAXS/WAXS patterns of mixtures of 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide ([Bm2im][N(CF3SO2)2]) and acetonitrile were also determined, with the results suggesting that [Bm2im][N(CF3SO2)2] is more ordered than [Bmim][N(CF3SO2)2] due to an enhancement in the short-range interactions.
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Affiliation(s)
- Sinead T Keaveney
- School of Chemistry, University of New South Wales , Sydney, NSW 2052, Australia
| | - Tamar L Greaves
- School of Science, College of Science, Engineering and Health, RMIT University , Melbourne, VIC 3001, Australia
| | | | - Jason B Harper
- School of Chemistry, University of New South Wales , Sydney, NSW 2052, Australia
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27
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Butler BJ, Thomas DS, Hook JM, Harper JB. NMR spectroscopy to follow reaction progress in ionic liquids. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2016; 54:423-428. [PMID: 25287592 DOI: 10.1002/mrc.4161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 09/05/2014] [Accepted: 09/15/2014] [Indexed: 06/03/2023]
Abstract
In order to understand reaction outcomes in ionic liquids, it is crucial to be able to follow the progress of these reactions. This review highlights the advantages of NMR spectroscopy over other analytical techniques in following reaction progress in ionic liquids, particularly addressing the practical aspects of the methodology and highlighting the range of processes that can be readily followed. Copyright © 2014 John Wiley & Sons, Ltd.
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Affiliation(s)
- Bradley J Butler
- School of Chemistry, University of New South Wales (UNSW), Sydney, NSW, 2052, Australia
| | - Donald S Thomas
- Nuclear Magnetic Resonance Facility, Mark Wainwright Analytical Centre, University of New South Wales (UNSW), Sydney, NSW, 2052, Australia
| | - James M Hook
- Nuclear Magnetic Resonance Facility, Mark Wainwright Analytical Centre, University of New South Wales (UNSW), Sydney, NSW, 2052, Australia
| | - Jason B Harper
- School of Chemistry, University of New South Wales (UNSW), Sydney, NSW, 2052, Australia
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28
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Hawker RR, Panchompoo J, Aldous L, Harper JB. Novel Chloroimidazolium‐Based Ionic Liquids: Synthesis, Characterisation and Behaviour as Solvents to Control Reaction Outcome. Chempluschem 2016; 81:574-583. [DOI: 10.1002/cplu.201600099] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 04/06/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Rebecca R. Hawker
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
| | - Janjira Panchompoo
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
| | - Leigh Aldous
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
| | - Jason B. Harper
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
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29
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Butler BJ, Harper JB. The effect of the structure of the cation of an ionic liquid on the rate of reaction at a phosphorus centre. J PHYS ORG CHEM 2016. [DOI: 10.1002/poc.3554] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Bradley J. Butler
- School of Chemistry University of New South Wales, UNSW Sydney 2052 Australia
| | - Jason B. Harper
- School of Chemistry University of New South Wales, UNSW Sydney 2052 Australia
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30
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Schaffarczyk McHale KS, Hawker RR, Harper JB. Nitrogen versus phosphorus nucleophiles – how changing the nucleophilic heteroatom affects ionic liquid solvent effects in bimolecular nucleophilic substitution processes. NEW J CHEM 2016. [DOI: 10.1039/c6nj00721j] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Changing the nucleophile gave different ionic liquid effects, showing the importance of interactions with all species along the reaction coordinate.
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Affiliation(s)
| | | | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- Sydney
- Australia
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31
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Keaveney ST, White BP, Haines RS, Harper JB. The effects of an ionic liquid on unimolecular substitution processes: the importance of the extent of transition state solvation. Org Biomol Chem 2016; 14:2572-80. [DOI: 10.1039/c5ob02598b] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An ionic liquid significantly increases benzylic carbocation formation due to favourable ionic liquid–transition state interactions. The magnitude of transition state solvation was shown to be critical, explaining the difference between this and previous cases.
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Affiliation(s)
| | | | | | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- Sydney
- Australia
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32
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D'Anna F, Millan D, Noto R. The ionic liquid effect on the Boulton–Katritzky reaction: a comparison between substrates of different structure. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.05.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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33
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Keaveney ST, Haines RS, Harper JB. Ionic liquid effects on a multistep process. Increased product formation due to enhancement of all steps. Org Biomol Chem 2015. [DOI: 10.1039/c5ob01214g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
An ionic liquid is shown to increase the rate of all three steps in this imine formation and the microscopic origins of such are investigated. The magnitude of this enhancement varies with the nature of the substituent, though in all cases the rate of imine formation is increased.
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Affiliation(s)
| | | | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- Sydney
- Australia
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34
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Keaveney ST, Haines RS, Harper JB. Developing principles for predicting ionic liquid effects on reaction outcome. The importance of the anion in controlling microscopic interactions. Org Biomol Chem 2015; 13:3771-80. [DOI: 10.1039/c4ob02482f] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Predictable changes in the rate constant of a condensation reaction were seen as the solvent composition was varied. The cation–nucleophile interaction could be controlled in a predictable manner; activation parameters varied linearly with the H-bond acceptor ability of the anions used.
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Affiliation(s)
| | | | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- Sydney
- Australia
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35
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Butler BJ, Harper JB. The effect of an ionic liquid on the rate of reaction at a phosphorus centre. NEW J CHEM 2015. [DOI: 10.1039/c4nj01224k] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Rate constant of a substitution at phosphorus varies with amount of ionic liquid present; enthalpic benefit offsets entropic cost.
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Affiliation(s)
- Bradley J. Butler
- School of Chemistry
- University of New South Wales
- UNSW Sydney 2052
- Australia
| | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- UNSW Sydney 2052
- Australia
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36
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Keaveney ST, Harper JB, Croft AK. Computational approaches to understanding reaction outcomes of organic processes in ionic liquids. RSC Adv 2015. [DOI: 10.1039/c4ra14676j] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The utility of using a combined experimental and computational approach for understanding ionic liquid media, and their effect on reaction outcome, is highlighted through a number of case studies.
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Affiliation(s)
| | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- Sydney
- Australia
| | - Anna K. Croft
- Department of Chemical and Environmental Engineering
- University of Nottingham
- University Park
- Nottingham
- UK
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37
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Kochly ED, Citrak S, Gathondu N, Amberchan G. Effect of ionic liquids in unimolecular solvolysis reactions involving carbocationic intermediates. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.10.145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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38
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Acevedo O. Simulating chemical reactions in ionic liquids using QM/MM methodology. J Phys Chem A 2014; 118:11653-66. [PMID: 25329366 DOI: 10.1021/jp507967z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The use of ionic liquids as a reaction medium for chemical reactions has dramatically increased in recent years due in large part to the numerous reported advances in catalysis and organic synthesis. In some extreme cases, ionic liquids have been shown to induce mechanistic changes relative to conventional solvents. Despite the large interest in the solvents, a clear understanding of the molecular factors behind their chemical impact is largely unknown. This feature article reviews our efforts developing and applying mixed quantum and molecular mechanical (QM/MM) methodology to elucidate the microscopic details of how these solvents operate to enhance rates and alter mechanisms for industrially and academically important reactions, e.g., Diels-Alder, Kemp eliminations, nucleophilic aromatic substitutions, and β-eliminations. Explicit solvent representation provided the medium dependence of the activation barriers and atomic-level characterization of the solute-solvent interactions responsible for the experimentally observed "ionic liquid effects". Technical advances are also discussed, including a linear-scaling pairwise electrostatic interaction alternative to Ewald sums, an efficient polynomial fitting method for modeling proton transfers, and the development of a custom ionic liquid OPLS-AA force field.
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Affiliation(s)
- Orlando Acevedo
- Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States
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39
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Manna A, Kumar A. Invoking Pairwise Interactions in Water-Promoted Diels-Alder Reactions by using Ionic Liquids as Cosolvents. Chemphyschem 2014; 15:3067-77. [DOI: 10.1002/cphc.201402338] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Indexed: 11/09/2022]
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40
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Keaveney ST, Schaffarczyk McHale KS, Haines RS, Harper JB. Developing principles for predicting ionic liquid effects on reaction outcome. A demonstration using a simple condensation reaction. Org Biomol Chem 2014; 12:7092-9. [DOI: 10.1039/c4ob01070a] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Predictions of the effects of the proportion and the components of an ionic liquid on the reaction rate are shown to correlate well with experimental results.
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Affiliation(s)
| | | | - Ronald S. Haines
- School of Chemistry
- University of New South Wales
- Sydney, Australia
| | - Jason B. Harper
- School of Chemistry
- University of New South Wales
- Sydney, Australia
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41
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Abstract
Ionic liquids are frequently touted as alternatives to traditional molecular solvents but are limited in their applicability as the outcome of reactions may be altered on moving from a molecular to an ionic solvent. This manuscript summarizes our progress towards a predictive framework through understanding how ionic solvents affect organic processes, with an emphasis on how these findings might be applied. Particularly, we will consider the importance of the mole fraction of the ionic liquid used, including some hitherto undisclosed results, as well as the importance of understanding the key interactions of the solvent with the components along the reaction coordinate.
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42
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Weber CC, Masters AF, Maschmeyer T. Steric, hydrogen-bonding and structural heterogeneity effects on the nucleophilic substitution of N-(p-fluorophenyldiphenylmethyl)-4-picolinium chloride in ionic liquids. Org Biomol Chem 2013; 11:2534-42. [DOI: 10.1039/c3ob40105g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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44
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Tanner EEL, Hawker RR, Yau HM, Croft AK, Harper JB. Probing the importance of ionic liquid structure: a general ionic liquid effect on an SNAr process. Org Biomol Chem 2013; 11:7516-21. [DOI: 10.1039/c3ob41634h] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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45
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Tanner EEL, Yau HM, Hawker RR, Croft AK, Harper JB. Does the cation really matter? The effect of modifying an ionic liquid cation on an SN2 process. Org Biomol Chem 2013; 11:6170-5. [DOI: 10.1039/c3ob41038b] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Keaveney ST, Harper JB. Towards reaction control using an ionic liquid: biasing outcomes of reactions of benzyl halides. RSC Adv 2013. [DOI: 10.1039/c3ra42820f] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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47
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Weber CC, Masters AF, Maschmeyer T. Pseudoverkapselung - Nanodomänen für verstärkte Reaktivität in ionischen Flüssigkeiten. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201206113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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48
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Weber CC, Masters AF, Maschmeyer T. Pseudo-Encapsulation-Nanodomains for Enhanced Reactivity in Ionic Liquids. Angew Chem Int Ed Engl 2012; 51:11483-6. [DOI: 10.1002/anie.201206113] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Indexed: 11/09/2022]
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49
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Weber CC, Masters AF, Maschmeyer T. Controlling Hydrolysis Reaction Rates with Binary Ionic Liquid Mixtures by Tuning Hydrogen-Bonding Interactions. J Phys Chem B 2012; 116:1858-64. [DOI: 10.1021/jp211543v] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Cameron C. Weber
- Laboratory of Advanced Catalysis
for Sustainability,
School of Chemistry, University of Sydney, Sydney 2006, Australia
| | - Anthony F. Masters
- Laboratory of Advanced Catalysis
for Sustainability,
School of Chemistry, University of Sydney, Sydney 2006, Australia
| | - Thomas Maschmeyer
- Laboratory of Advanced Catalysis
for Sustainability,
School of Chemistry, University of Sydney, Sydney 2006, Australia
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50
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Yau HM, Croft AK, Harper JB. Investigating the origin of entropy-derived rate accelerations in ionic liquids. Faraday Discuss 2012; 154:365-71; discussion 439-64, 465-71. [DOI: 10.1039/c1fd00060h] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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