1
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Dielectric behavior of water in [bmim] [$$\hbox {Tf}_2$$N] room-temperature ionic liquid: molecular dynamic study. Theor Chem Acc 2021. [DOI: 10.1007/s00214-021-02825-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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2
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Greaves TL, Schaffarczyk McHale KS, Burkart-Radke RF, Harper JB, Le TC. Machine learning approaches to understand and predict rate constants for organic processes in mixtures containing ionic liquids. Phys Chem Chem Phys 2021; 23:2742-2752. [PMID: 33496292 DOI: 10.1039/d0cp04227g] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The ability to tailor the constituent ions in ionic liquids (ILs) is highly advantageous as it provides access to solvents with a range of physicochemical properties. However, this benefit also leads to large compositional spaces that need to be explored to optimise systems, often involving time consuming experimental work. The use of machine learning methods is an effective way to gain insight based on existing data, to develop structure-property relationships and to allow the prediction of ionic liquid properties. Here we have applied machine learning models to experimentally determined rate constants of a representative organic process (the reaction of pyridine with benzyl bromide) in IL-acetonitrile mixtures. Multiple linear regression (MLREM) and artificial neural networks (BRANNLP) were both able to model the data well. The MLREM model was able to identify the structural features on the cations and anions that had the greatest effect on the rate constant. Secondly, predictive MLREM and BRANNLP models were developed from the full initial set of rate constant data. From these models, a large number of predictions (>9000) of rate constant were made for mixtures of different ionic liquids, at different proportions of ionic liquid and molecular solvent, at different temperatures. A selection of these predictions were tested experimentally, including through the preparation of novel ionic liquids, with overall good agreement between the predicted and experimental data. This study highlights the benefits of using machine learning methods on kinetic data in ionic liquid mixtures to enable the development of rigorous structure-property relationships across multiple variables simultaneously, and to predict properties of new ILs and experimental conditions.
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Affiliation(s)
- Tamar L Greaves
- 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.
| | - Tu C Le
- College of Science Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia.
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3
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Liu KTC, Haines RS, Harper JB. The effect of bisimidazolium-based ionic liquids on a bimolecular substitution process. Are two head(group)s better than one? Org Biomol Chem 2020; 18:7388-7395. [PMID: 32930294 DOI: 10.1039/d0ob01500h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A homologous series of biscationic ionic liquids based on two imidazolium centres, separated by alkyl chains of varying length, were examined as solvents for a bimolecular substitution reaction across a range of proportions of ionic liquid in the reaction mixture. Their effects on the rate constant of the process were compared to monocationic ionic liquids, with generally a greater rate constant increase observed. Importantly, it was observed that the magnitude of the effect was shown to vary with the length of the linking chain. To investigate the origins of these solvent effects, temperature dependent kinetic studies were performed to obtain activation parameters at high and low mole fractions of ionic liquid. The observed activation parameters showed the rate constant enhancement was due to interaction of the ionic liquid with the starting materials, consistent with previous results. Significantly, however, these data also showed that the balance of enthalpic and entropic effects varied dramatically with the length of the alkyl chain between the cationic centres.
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Affiliation(s)
- Kenny T-C Liu
- 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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4
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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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5
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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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6
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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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7
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Yalcin D, Christofferson AJ, Drummond CJ, Greaves TL. Solvation properties of protic ionic liquid–molecular solvent mixtures. Phys Chem Chem Phys 2020; 22:10995-11011. [DOI: 10.1039/d0cp00201a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In this study, we have investigated the solvation properties of binary mixtures of PILs with molecular solvents. The selected binary solvent systems are the PILs ethylammonium nitrate (EAN) and propylammonium nitrate (PAN) combined with either water, methanol, acetonitrile or DMSO.
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Affiliation(s)
- Dilek Yalcin
- School of Science
- College of Science
- Engineering and Health
- RMIT University
- Melbourne
| | | | - Calum J. Drummond
- School of Science
- College of Science
- Engineering and Health
- RMIT University
- Melbourne
| | - Tamar L. Greaves
- School of Science
- College of Science
- Engineering and Health
- RMIT University
- Melbourne
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8
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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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9
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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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10
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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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11
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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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12
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Xiao Y, Huang X. The physicochemical properties of a room-temperature liquidus binary ionic liquid mixture of [HNMP][CH 3SO 3]/[Bmim]Cl and its application for fructose conversion to 5-hydroxymethylfurfural. RSC Adv 2018; 8:18784-18791. [PMID: 35539654 PMCID: PMC9080599 DOI: 10.1039/c8ra03604g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 05/17/2018] [Indexed: 11/29/2022] Open
Abstract
Via heating first and then cooling, binary ionic liquid (IL) mixture of N-methyl-2-pyrrolidonium methylsulfonate ([HNMP][CH3SO3]) and 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) could form a liquid at room temperature. The glass-transition temperature (T g) characterized by DSC depends on its composition with T g being as low as -63 °C. The physicochemical properties of the binary IL mixtures also vary with the composition. With the increase of the mole fraction of [Bmim]Cl, the hydrogen-bond accepting ability (β) of the binary IL mixture increases, but the hydrogen-bond donating ability (α) deceases. In this binary IL mixture, fructose could be effectively converted into 5-hydroxymethylfurfural (HMF) at room temperature. The HMF yields at a given time are found to be well correlated with the physicochemical properties of the binary mixture, especially the α and β values. Under specified conditions, the present IL mixture as medium for fructose dehydration into HMF is comparable to the medium formed by ILs and alcohol, where the alcohols have negative effect on the HMF formation.
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Affiliation(s)
- Yuyan Xiao
- Key Lab for Colloid and Interface Chemistry of the Education Ministry of China, Shandong University Jinan 250100 P. R. China
| | - Xirong Huang
- Key Lab for Colloid and Interface Chemistry of the Education Ministry of China, Shandong University Jinan 250100 P. R. China
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13
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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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14
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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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15
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16
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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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17
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Wang Z, Xi H, Kong L, Zuo Y, Shi Z, Zhao S. Solubility and selective oxidation of 2-chloroethyl ethyl sulfide in imidazole-based ionic liquids. MOLECULAR CATALYSIS 2017. [DOI: 10.1016/j.molcata.2016.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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18
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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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19
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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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20
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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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21
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Gondosiswanto R, Gunawan CA, Hibbert DB, Harper JB, Zhao C. Microcontact Printing of Thiol-Functionalized Ionic Liquid Microarrays for "Membrane-less" and "Spill-less" Gas Sensors. ACS APPLIED MATERIALS & INTERFACES 2016; 8:31368-31374. [PMID: 27782398 DOI: 10.1021/acsami.6b08876] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Lab-on-a-chip systems have gained significant interest for both chemical synthesis and assays at the micro-to-nanoscale with a unique set of benefits. However, solvent volatility represents one of the major hurdles to the reliability and reproducibility of the lab-on-a-chip devices for large-scale applications. Here we demonstrate a strategy of combining nonvolatile and functionalized ionic liquids with microcontact printing for fabrication of "wall-less" microreactors and microfluidics with high reproducibility and high throughput. A range of thiol-functionalized ionic liquids have been synthesized and used as inks for microcontact printing of ionic liquid microdroplet arrays onto gold chips. The covalent bonds formed between the thiol-functionalized ionic liquids and the gold substrate offer enhanced stability of the ionic liquid microdroplets, compared to conventional nonfunctionalized ionic liquids, and these microdroplets remain stable in a range of nonpolar and polar solvents, including water. We further demonstrate the use of these open ionic liquid microarrays for fabrication of "membrane-less" and "spill-less" gas sensors with enhanced reproducibility and robustness. Ionic-liquid-based microarray and microfluidics fabricated using the described microcontact printing may provide a versatile platform for a diverse number of applications at scale.
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Affiliation(s)
| | | | - David B Hibbert
- School of Chemistry, UNSW Australia , Sydney, NSW 2052, Australia
| | - Jason B Harper
- School of Chemistry, UNSW Australia , Sydney, NSW 2052, Australia
| | - Chuan Zhao
- School of Chemistry, UNSW Australia , Sydney, NSW 2052, Australia
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22
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Keaveney ST, Schaffarczyk McHale KS, Stranger JW, Ganbold B, Price WS, Harper JB. NMR Diffusion Measurements as a Simple Method to Examine Solvent-Solvent and Solvent-Solute Interactions in Mixtures of the Ionic Liquid [Bmim][N(SO2CF3)2] and Acetonitrile. Chemphyschem 2016; 17:3853-3862. [DOI: 10.1002/cphc.201600927] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Sinead T. Keaveney
- School of Chemistry; University of New South Wales, UNSW; Sydney NSW 2052 Australia
| | | | - James W. Stranger
- Nanoscale Organisation and Dynamics Group; Western Sydney University; Locked Bag 1797, Penrith NSW 2751 Australia
| | - Batchimeg Ganbold
- Nanoscale Organisation and Dynamics Group; Western Sydney University; Locked Bag 1797, Penrith NSW 2751 Australia
| | - William S. Price
- Nanoscale Organisation and Dynamics Group; Western Sydney University; Locked Bag 1797, Penrith NSW 2751 Australia
| | - Jason B. Harper
- School of Chemistry; University of New South Wales, UNSW; Sydney NSW 2052 Australia
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23
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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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24
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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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25
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Pavez P, Millán D, Rojas M, Morales JI, Santos JG. Reaction Mechanism in Ionic Liquids: Kinetics and Mechanism of the Aminolysis of 4-Nitrophenyl Acetate. INT J CHEM KINET 2016. [DOI: 10.1002/kin.20994] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Paulina Pavez
- Facultad de Química; Pontificia Universidad Católica de Chile; Casilla 306 Santiago 6094411 Chile
| | - Daniela Millán
- Facultad de Química; Pontificia Universidad Católica de Chile; Casilla 306 Santiago 6094411 Chile
| | - Mabel Rojas
- Facultad de Química; Pontificia Universidad Católica de Chile; Casilla 306 Santiago 6094411 Chile
| | - Javiera I. Morales
- Facultad de Química; Pontificia Universidad Católica de Chile; Casilla 306 Santiago 6094411 Chile
| | - José G. Santos
- Facultad de Química; Pontificia Universidad Católica de Chile; Casilla 306 Santiago 6094411 Chile
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26
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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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27
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Pavez P, Millán D, Morales J, Rojas M, Céspedes D, Santos JG. Reaction mechanisms in ionic liquids: the kinetics and mechanism of the reaction of O,O-diethyl (2,4-dinitrophenyl) phosphate triester with secondary alicyclic amines. Org Biomol Chem 2016; 14:1421-7. [DOI: 10.1039/c5ob02128f] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In the title reaction, the ionic liquids used stabilized the zwitterionic pentacoordinate intermediate (P±), leading to a change in the mechanism from concerted to stepwise.
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Affiliation(s)
- Paulina Pavez
- Facultad de Química. Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - Daniela Millán
- Facultad de Química. Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - Javiera Morales
- Facultad de Química. Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - Mabel Rojas
- Facultad de Química. Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - Daniel Céspedes
- Facultad de Química. Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
| | - José G. Santos
- Facultad de Química. Pontificia Universidad Católica de Chile
- Santiago 6094411
- Chile
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28
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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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29
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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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30
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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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31
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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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32
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Priede E, Brica S, Bakis E, Udris N, Zicmanis A. Ionic liquids as solvents for the Knoevenagel condensation: understanding the role of solvent–solute interactions. NEW J CHEM 2015. [DOI: 10.1039/c5nj01906k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The hydrogen bond basicityβof ionic liquids, as demonstrated by the NMR studies and the Kamlet–Taft linear solvation energy relationship, was confirmed to be the dominant solvent descriptor determining the rate of the Knoevenagel condensation.
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Affiliation(s)
- Elina Priede
- University of Latvia
- Faculty of Chemistry
- Riga
- Latvia
| | | | - Eduards Bakis
- Imperial College London
- Department of Chemistry
- South Kensington Campus
- London SW7 2AZ
- UK
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