Specific-ion effects in non-aqueous systems

Mazzini, Virginia; Craig, Vincent S. J.

doi:10.1016/j.cocis.2016.06.009

Cited by 65 publications

(96 citation statements)

References 73 publications

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“…In contrast to simple electrostatic mean-field approaches, recent numerical and experimental findings indeed revealed the occurrence of various ion complex states. Hence, ions and solvent molecules aggregate within the Bjerrum length to ion-solvent complexes with distinct stoichiometries, as influenced by the ion species, the ion concentration, and the molecular properties of the solvent molecules [45,53,63,[67][68][69][70][71][72][73][74][75][76][77][78].…”

Section: Distinct States Of Ion Complexesmentioning

confidence: 99%

“…For some solvents and specifically for water, differences in the complex formation tendencies for distinct ions are observed, which can be rationalized by the influence of specific ion effects [38,54,63,68,70,75,[83][84][85][86]. These effects are often observed in aqueous solutions, whereas studies of specific ion effects in organic solvents are rather sparse [30,[76][77][78]87]. A series of seminal studies [35][36][37] regarding the solubility of various lithium salts in acetonitrile reveals the following order, LiPF 6 < LiFSI < LiTFSI ≤ LiClO 4 < LiBF 4 LiCF 3 CO 2 , which coincides with the observed tendency of ion complex formation.…”

Section: Specific Ion Effectsmentioning

confidence: 99%

“…Hence, smaller ions such as F − and Li + are kosmotropes, meaning that they are water structure makers, whereas larger ions such as I − and SCN − are chaotropes, which emphasizes the fact that these species have to be considered as water structure breakers [53,54,63,70]. With regard to these definitions, it has to be clearly pointed out that kosmotropic and chaotropic properties are solely defined for ions in aqueous solutions, whereas the occurrence of comparable effects in aprotic solvents is currently under debate [30,76,83]. Chaotropic and kosmotropic effects on the water structure can be observed in terms of viscosity variations associated with the Jones-Dole viscosity B coefficient, as well as with regard to the dynamic behavior of water molecules in terms of dipolar relaxation times [53,63,87].…”

Section: Specific Ion Effectsmentioning

confidence: 99%

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Properties of Ion Complexes and Their Impact on Charge Transport in Organic Solvent-Based Electrolyte Solutions for Lithium Batteries: Insights from a Theoretical Perspective

2018

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Electrolyte formulations in standard lithium ion and lithium metal batteries are complex mixtures of various components. In this article, we review molecular key principles of ion complexes in multicomponent electrolyte solutions in regards of their influence on charge transport mechanisms. We outline basic concepts for the description of ion–solvent and ion–ion interactions, which can be used to rationalize recent experimental and numerical findings concerning modern electrolyte formulations. Furthermore, we discuss benefits and drawbacks of empirical concepts in comparison to molecular theories of solution for a more refined understanding of ion behavior in organic solvents. The outcomes of our discussion provide a rational for beneficial properties of ions, solvent, co-solvent and additive molecules, and highlight possible routes for further improvement of novel electrolyte solutions.

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Section: Distinct States Of Ion Complexesmentioning

confidence: 99%

Section: Specific Ion Effectsmentioning

confidence: 99%

Section: Specific Ion Effectsmentioning

confidence: 99%

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Properties of Ion Complexes and Their Impact on Charge Transport in Organic Solvent-Based Electrolyte Solutions for Lithium Batteries: Insights from a Theoretical Perspective

2018

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“…It has been established that DMSO behaves similarly under the influence of different ions (i.e. the physicochemical properties of both solvents change in accordance with the same lyotropic series) 22,23 . While most bisguanidines were studied as 0.05 M solutions, unfortunately only the sulphates of GUA and GLY were sufficiently soluble to produce informative signals ( Fig.…”

Section: Comparison Of 1 H Nmr Spectra Although Not Ideal In Order mentioning

confidence: 99%

Exploring ion-ion preferences through structure-property correlations: amino acid-derived, bis(guanidinium) disiloxane salts

Tabisz

Rozwadowski

Katrusiak

et al. 2020

Sci Rep

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present study that valuable information could be obtained from comparative analysis of series of compounds: complicated enough to include more than one functionality, yet simple enough to allow for differentiation of their individual impact on bulk physicochemical properties. Starting with the abovementioned lysozyme/ionic liquid behaviour discrepancy and wanting to also investigate the structuring effect of anions on the separating organic phase, we decided to synthesize amino acid-linked bis(guanidines), in which the polar moieties are separated by a siloxane bridge. This idea stemmed from a previous study, which revealed an abnormally low water solubility of the prepared 1,3-bis(3-guanidinopropyl)-t etramethyldisiloxane nitrate (parent chloride was fully water-miscible) 17. Addition of amide bonds seemed very attractive, as they often co-exist with guanidine moieties in many polypeptides and are a key ingredient in their higher-than-primary structure. Guanidines, on the other hand, have well-established "chaotropic" properties in their own right 18. Siloxane bridges, though fairly chemically and very thermally resistant, impart a strong tendency for disorganization and non-crystallinity on the molecule, which stems from the extremely low energy barrier for rotation around the Si-O bond 19. This results in most siloxanes presenting as liquids, oils or waxy solids at room temperature (a point of connection with ionic liquids). The apparent crystallinity of the abovementioned nitrate was yet another reason for choosing that particular class of compounds. Apart from the obvious advantage of easily comparable results, one of the drawbacks of articles referring to Hofmeister series as a common denominator is the limitation of studied anions to those with well-established places on that spectrum: phosphate, sulphate, halides, nitrate, perchlorate and thiocyanate. In an effort to find more subtle differences, we expanded our search. For example, while the charge density difference between sulphate and perchlorate explains why these two geometrically similar oxoanions exert significantly different influences on water solutions, we chose chromate and molybdate (same geometry and charge) instead. Azide, an ion very rarely studied in this context, was also included-due to its specific linear geometry (similar to thiocyanate) and significant electronic contribution from the characteristic − N = N + = N − resonance structure. Results and Discussion Design and synthesis. The intramolecular hydrogen bonding between amide moieties determines the

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“…Substantial attention has been paid to Hofmeister (Kunz et al 2004) phenomena because of their relevance to a broad range of fields. A few examples of physical behaviour obeying the Hofmeister series include enzyme activity (Pinna et al 2005), protein stability (Broering and Bommarius 2007;Zhao 2016), protein-protein interactions (Yeh et al 2010), protein crystallization (dos Santos et al 2017) and bacterial growth (Lo Nostro et al 2005), as well as solvent properties in nonaqueous systems (Mazzini and Craig 2016 are ubiquitous, the molecular-level mechanisms by which ions operate are only just beginning to be unravelled (Schwierz et al 2016;Zavitsas 2016). Understanding the molecular nature of ion macromolecule or interface interactions is also important for membrane protein function, bilayer dynamics and cellular biophysics (Valley et al 2011;Woolf 2013).…”

Section: Introductionmentioning

confidence: 99%

Counting ions and other nucleophiles at surfaces by chemical trapping

2017

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The interfaces of membranes and other aggregates are determined by the polarity, electrical charge, molecular volume, degrees of motional freedom and packing density of the head groups of the amphiphiles. These properties also determine the type of bound ion (ion selectivity) and its local density, i.e. concentration defined by choosing an appropriate volume element at the aggregate interface. Bulk and local ion concentrations can differ by orders of magnitude. The relationships between ion (or other compound) concentrations in the bulk solvent and in the interface are complex but, in some cases, well established. As the local ion concentration, rather than that in the bulk, controls a variety of properties of membranes, micelles, vesicles and other objects of theoretical and applied interests, measurement of local (interfacial, bound) ion concentrations is of relevance for understanding and characterizing such aggregates. Many experimental methods for estimating ion distributions between the bulk solution and the interface provide indirect estimates because they are based on concentration-dependent properties, rather than concentration measurements. Dediazoniation, i.e. the loss of N, of a substituted diazophenyl derivative provides a tool for determining the number of nucleophiles (including neutral or negatively charged ions) surrounding the diazophenyl derivative prior to the dediazoniation event. This reaction, defined as chemical trapping, and the appropriate reference points obtained in bulk solution allow direct measurements of local concentrations of a variety of nucleophiles at the surface of membranes and other aggregates. Here we review our contributions of our research group to the use, and understanding, of this method and applications of chemical trapping to the description of local concentrations of ions and other nucleophiles in micelles, reverse micelles, vesicles and solvent mixtures. Among other results, we have shown that interfacial water determines micellar shape, zwitterionic vesicle-forming amphiphiles display ion selectivity and urea does not accumulate at micellar interfaces. We have also shown that reaction products can be predicted from the composition of the initial state, even in non-ideal solvent mixtures, supporting the usefulness of chemical trapping as a method to determine local concentrations. In addition, we have analysed the mechanism of dediazoniation, both on theoretical and experimental basis, and concluded that the formation of a free phenyl cation is not a necessary part of the reaction pathway.

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Specific-ion effects in non-aqueous systems

Cited by 65 publications

References 73 publications

Properties of Ion Complexes and Their Impact on Charge Transport in Organic Solvent-Based Electrolyte Solutions for Lithium Batteries: Insights from a Theoretical Perspective

Properties of Ion Complexes and Their Impact on Charge Transport in Organic Solvent-Based Electrolyte Solutions for Lithium Batteries: Insights from a Theoretical Perspective

Exploring ion-ion preferences through structure-property correlations: amino acid-derived, bis(guanidinium) disiloxane salts

Counting ions and other nucleophiles at surfaces by chemical trapping

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