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Rudani BA, Jakubowski A, Kriegs H, Wiegand S. Deciphering the guanidinium cation: Insights into thermal diffusion. J Chem Phys 2024; 160:214502. [PMID: 38828819 DOI: 10.1063/5.0215843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 05/16/2024] [Indexed: 06/05/2024] Open
Abstract
Thermophoresis, or thermodiffusion, is becoming a more popular method for investigating the interactions between proteins and ligands due to its high sensitivity to the interactions between solutes and water. Despite its growing use, the intricate mechanisms behind thermodiffusion remain unclear. This gap in knowledge stems from the complexities of thermodiffusion in solvents that have specific interactions as well as the intricate nature of systems that include many components with both non-ionic and ionic groups. To deepen our understanding, we reduce complexity by conducting systematic studies on aqueous salt solutions. In this work, we focused on how guanidinium salt solutions behave in a temperature gradient, using thermal diffusion forced Rayleigh scattering experiments at temperatures ranging from 15 to 35 °C. We looked at the thermodiffusive behavior of four guanidinium salts (thiocyanate, iodide, chloride, and carbonate) in solutions with concentrations ranging from 1 to 3 mol/kg. The guanidinium cation is disk-shaped and is characterized by flat hydrophobic surfaces and three amine groups, which enable directional hydrogen bonding along the edges. We compare our results to the behavior of salts with spherical cations, such as sodium, potassium, and lithium. Our discussions are framed around how different salts are solvated, specifically in the context of the Hofmeister series, which ranks ions based on their effects on the solvation of proteins.
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Affiliation(s)
- Binny A Rudani
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Andre Jakubowski
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Hartmut Kriegs
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
| | - Simone Wiegand
- IBI-4:Biomacromolecular Systems and Processes, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany
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2
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Patrick SC, Beer PD, Davis JJ. Solvent effects in anion recognition. Nat Rev Chem 2024; 8:256-276. [PMID: 38448686 DOI: 10.1038/s41570-024-00584-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2024] [Indexed: 03/08/2024]
Abstract
Anion recognition is pertinent to a range of environmental, medicinal and industrial applications. Recent progress in the field has relied on advances in synthetic host design to afford a broad range of potent recognition motifs and novel supramolecular structures capable of effective binding both in solution and at derived molecular films. However, performance in aqueous media remains a critical challenge. Understanding the effects of bulk and local solvent on anion recognition by host scaffolds is imperative if effective and selective detection in real-world media is to be viable. This Review seeks to provide a framework within which these effects can be considered both experimentally and theoretically. We highlight proposed models for solvation effects on anion binding and discuss approaches to retain strong anion binding in highly competitive (polar) solvents. The synthetic design principles for exploiting the aforementioned solvent effects are explored.
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Affiliation(s)
| | - Paul D Beer
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Jason J Davis
- Department of Chemistry, University of Oxford, Oxford, UK.
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3
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Hegaard F, Biro R, Ehtiati K, Thormann E. Ion-Specific Antipolyelectrolyte Effect on the Swelling Behavior of Polyzwitterionic Layers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:1456-1464. [PMID: 36656651 DOI: 10.1021/acs.langmuir.2c02798] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In this study, we systematically investigate the interactions between mobile ions generated from added salts and immobile charges within a sulfobetaine-based polyzwitterionic film in the presence of five salts (KCl, KBr, KSCN, LiCl, and CsCl). The sulfobetaine groups contain quaternary alkylammonium and sulfonate groups, giving the positive and negative charges. The swelling of the zwitterionic film in the presence of different salts is compared with the swelling behavior of a polycationic or polyanionic film containing the same charged groups. For such a comparative study, we design cross-linked terpolymer films with similar thicknesses, cross-link densities, and charge fractions, but with varying charged moieties. While the addition of salt in general leads to a collapse of both cationic and anionic films, the presence of specific types of mobile anions (Cl-, Br-, and SCN-) considerably influences the swelling behavior of polycationic films. We attribute this observation to a different degree of ion-pair formations between the different types of anionic counterions and the immobile cationic quaternary alkylammonium groups in the films where highly polarizable counterions such as SCN- lead to a high degree of ion pairing and less polarizable counterions, such as Cl-, cause a low degree of ion pairing. Conversely, we do not observe any substantial effect of varying the type of cationic counterions (K+, Li+, and Cs+), which we assign to the lack of ion pairing between the weakly polarizable cations and the immobile anionic sulfonate groups in the films. In addition, we observe that the zwitterionic films swell with increasing ionic strength and the degree of swelling is anion dependent, which is in agreement with previous reports on the "antipolyelectrolyte effect". Herein, we explain this ion-specific swelling behavior with the different cation and anion abilities to form ion pairs with quaternary alkylammonium and sulfonate in the sulfobetaine groups.
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Affiliation(s)
- Frederik Hegaard
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Robert Biro
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Koosha Ehtiati
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Esben Thormann
- Department of Chemistry, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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4
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Balos V, Kaliannan NK, Elgabarty H, Wolf M, Kühne TD, Sajadi M. Time-resolved terahertz-Raman spectroscopy reveals that cations and anions distinctly modify intermolecular interactions of water. Nat Chem 2022; 14:1031-1037. [PMID: 35773490 PMCID: PMC9417992 DOI: 10.1038/s41557-022-00977-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 05/16/2022] [Indexed: 11/09/2022]
Abstract
The solvation of ions changes the physical, chemical and thermodynamic properties of water, and the microscopic origin of this behaviour is believed to be ion-induced perturbation of water's hydrogen-bonding network. Here we provide microscopic insights into this process by monitoring the dissipation of energy in salt solutions using time-resolved terahertz-Raman spectroscopy. We resonantly drive the low-frequency rotational dynamics of water molecules using intense terahertz pulses and probe the Raman response of their intermolecular translational motions. We find that the intermolecular rotational-to-translational energy transfer is enhanced by highly charged cations and is drastically reduced by highly charged anions, scaling with the ion surface charge density and ion concentration. Our molecular dynamics simulations reveal that the water-water hydrogen-bond strength between the first and second solvation shells of cations increases, while it decreases around anions. The opposite effects of cations and anions on the intermolecular interactions of water resemble the effects of ions on the stabilization and denaturation of proteins.
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Affiliation(s)
- Vasileios Balos
- Fritz Haber Institute of the Max-Planck Society, Berlin, Germany. .,IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco, Madrid, Spain.
| | - Naveen Kumar Kaliannan
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Paderborn, Germany
| | - Hossam Elgabarty
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Paderborn, Germany.
| | - Martin Wolf
- Fritz Haber Institute of the Max-Planck Society, Berlin, Germany
| | - Thomas D Kühne
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Paderborn, Germany
| | - Mohsen Sajadi
- Fritz Haber Institute of the Max-Planck Society, Berlin, Germany. .,Dynamics of Condensed Matter and Center for Sustainable Systems Design, Chair of Theoretical Chemistry, University of Paderborn, Paderborn, Germany.
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5
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Hpone Myint K, Ding W, Willard AP. The Influence of Spectator Cations on Solvent Reorganization Energy Is a Short-Range Effect. J Phys Chem B 2021; 125:1429-1438. [PMID: 33525875 DOI: 10.1021/acs.jpcb.0c09895] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this manuscript, we use classical molecular dynamics simulation to explore the origin of specific cation effects on the rates of bulk-phase aqueous electron transfer (ET) reactions. We consider 0.6 M solutions of Cl- and a series of different cations: Li+, Na+, K+, Rb+, and Cs+. We evaluate the collective electrostatic fluctuations that drive Marcus-like ET and find that they are essentially unaffected by changes in the cationic species. This finding implies that the structure making/breaking properties of various cations do not exert a significant influence on bulk-phase ET reactions. We evaluate the role of ion pairing in these specific cation effects and find, unsurprisingly, that model redox anions that are more highly charged tend to pair more effectively with spectator cations than their monovalent counterparts. We demonstrate that this ion pairing significantly affects local electrostatic fluctuations for the anionic redox species and thus conclude that ion pairing is one of the likely sources of rate-dependent cation effects in aqueous ET reactions.
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Affiliation(s)
- Kyaw Hpone Myint
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Wendu Ding
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Adam P Willard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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6
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Chen J, Qian K, Xiao K, Luo J, Li H, Ma T, Kortz U, Tsige M, Liu T. Co-ion Effects in the Self-Assembly of Macroions: From Co-ions to Co-macroions and to the Unique Feature of Self-Recognition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:10519-10527. [PMID: 32787054 DOI: 10.1021/acs.langmuir.0c01797] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Macroions, as soluble ions with a size on the nanometer scale, show unique solution behavior different from those of simple ions and large colloidal suspensions. In macroionic solutions, the counterions are known to be important and well-explored. However, the role of co-ions (ions carrying the same type of charge as the macroions) is often ignored. Here, through experimental and simulation studies, we demonstrate the role of co-ions as a function of co-ion size on their interaction with the macroions (using {Mo72Fe30} and {SrPd12} as models) and the related self-assembly into blackberry-type structures in dilute solutions. Several regimes of unique co-ion effects are clearly identified: small ions (halides, oxoacid ions), subnanometer-scaled bulky ions (lacunary Keggin and dodecaborate ions), and those with sizes comparable to the macroions. Small co-ions have no observable effect on the self-assembly of fully hydrophilic {Mo72Fe30}, while due to hydrophobic interaction and intermolecular hydrogen bonds, the small co-ions show influences on the self-assembly of hydrophobic {SrPd12}. Subnanometer ions, a.k.a. "superchaotropic ions", are still too small to assemble into a blackberry by themselves, but they can coassemble with the macroions, showing a strong interaction with the macroionic system. When the co-ion size is comparable to that of the macroions, they assemble independently instead of assembling with the macroions, leading to the previously reported unique self-recognition phenomenon for macroions.
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Affiliation(s)
- Jiahui Chen
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Kun Qian
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Kexing Xiao
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Jiancheng Luo
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Hui Li
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Tian Ma
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kortz
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany
| | - Mesfin Tsige
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Tianbo Liu
- Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, United States
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7
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The Hofmeister series: Specific ion effects in aqueous polymer solutions. J Colloid Interface Sci 2019; 555:615-635. [PMID: 31408761 DOI: 10.1016/j.jcis.2019.07.067] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 12/21/2022]
Abstract
Specific ion effects in aqueous polymer solutions have been under active investigation over the past few decades. The current state-of-the-art research is primarily focused on the understanding of the mechanisms through which ions interact with macromolecules and affect their solution stability. Hence, we herein first present the current opinion on the sources of ion-specific effects and review the relevant studies. This includes a summary of the molecular mechanisms through which ions can interact with polymers, quantification of the affinity of ions for the polymer surface, a thermodynamic description of the effects of salts on polymer stability, as well as a discussion on the different forces that contribute to ion-polymer interplay. Finally, we also highlight future research issues that call for further scrutiny. These include fundamental questions on the mechanisms of ion-specific effects and their correlation with polymer properties as well as a discussion on the specific ion effects in more complex systems such as mixed electrolyte solutions.
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8
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Assaf KI, Nau WM. The Chaotropic Effect as an Assembly Motif in Chemistry. Angew Chem Int Ed Engl 2018; 57:13968-13981. [PMID: 29992706 PMCID: PMC6220808 DOI: 10.1002/anie.201804597] [Citation(s) in RCA: 194] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/01/2018] [Indexed: 11/26/2022]
Abstract
Following up on scattered reports on interactions of conventional chaotropic ions (for example, I- , SCN- , ClO4- ) with macrocyclic host molecules, biomolecules, and hydrophobic neutral surfaces in aqueous solution, the chaotropic effect has recently emerged as a generic driving force for supramolecular assembly, orthogonal to the hydrophobic effect. The chaotropic effect becomes most effective for very large ions that extend beyond the classical Hofmeister scale and that can be referred to as superchaotropic ions (for example, borate clusters and polyoxometalates). In this Minireview, we present a continuous scale of water-solute interactions that includes the solvation of kosmotropic, chaotropic, and hydrophobic solutes, as well as the creation of void space (cavitation). Recent examples for the association of chaotropic anions to hydrophobic synthetic and biological binding sites, lipid bilayers, and surfaces are discussed.
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Affiliation(s)
- Khaleel I. Assaf
- Department of Life Sciences and ChemistryJacobs University BremenCampus Ring 128759BremenGermany
| | - Werner M. Nau
- Department of Life Sciences and ChemistryJacobs University BremenCampus Ring 128759BremenGermany
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9
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Affiliation(s)
- Khaleel I. Assaf
- Department of Life Sciences and Chemistry; Jacobs University Bremen; Campus Ring 1 28759 Bremen Deutschland
| | - Werner M. Nau
- Department of Life Sciences and Chemistry; Jacobs University Bremen; Campus Ring 1 28759 Bremen Deutschland
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10
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Zhang Q, Pan Z, Zhang L, Zhang R, Chen Z, Jin T, Wu T, Chen X, Zhuang W. Ion effect on the dynamics of water hydrogen bonding network: A theoretical and computational spectroscopy point of view. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2018. [DOI: 10.1002/wcms.1373] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Qiang Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
- Department of ChemistryBohai UniversityJinzhouChina
| | - Zhijun Pan
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Ruiting Zhang
- School of Physics and Optoelectronic EngineeringXidian UniversityXi'anChina
| | - Zhening Chen
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Tan Jin
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Tianmin Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Xian Chen
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
| | - Wei Zhuang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouChina
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11
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Fernandez-Alvarez R, Ďorďovič V, Uchman M, Matějíček P. Amphiphiles without Head-and-Tail Design: Nanostructures Based on the Self-Assembly of Anionic Boron Cluster Compounds. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3541-3554. [PMID: 29144761 DOI: 10.1021/acs.langmuir.7b03306] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Anionic boron cluster compounds (ABCCs) are intrinsically amphiphilic building blocks suitable for nanochemistry. ABCCs are involved in atypical weak interactions, notably dihydrogen bonding, due to their peculiar polyhedral structure, consisting of negatively charged B-H units. The most striking feature of ABCCs that differentiates them from typical surfactants is the lack of head-and-tail structure. Furthermore, their structure can be described as intrinsically amphiphilic or aquaneutral. Therefore, classical terms established to describe self-assembly of classical amphiphiles are insufficient and need to be reconsidered. The opinions and theories focused on the solution behavior of ABCCs are briefly discussed. Moreover, a comparison between ABCCs with other amphiphilic systems is made focusing on the explanation of enthalpy-driven micellization or relations between hydrophobic and chaotropic effects. Despite the unusual structure, ABCCs still show self- and coassembly properties comparable to classical amphiphiles such as ionic surfactants. They self-assemble into micelles in water according to the closed association model. The most typical features of ABCCs solution behavior is demonstrated on calorimetry, NMR spectroscopy, and tensiometry experiments. Altogether, the unique features of ABCCs makes them a valuable inclusion into the nanochemisty toolbox to develop novel nanostructures both alone and with other molecules.
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Affiliation(s)
- Roberto Fernandez-Alvarez
- Department of Physical and Macromolecular Chemistry, Faculty of Science , Charles University , Hlavova 2030 , 128 40 Prague 2 , Czechia
| | - Vladimír Ďorďovič
- Department of Physical and Macromolecular Chemistry, Faculty of Science , Charles University , Hlavova 2030 , 128 40 Prague 2 , Czechia
| | - Mariusz Uchman
- Department of Physical and Macromolecular Chemistry, Faculty of Science , Charles University , Hlavova 2030 , 128 40 Prague 2 , Czechia
| | - Pavel Matějíček
- Department of Physical and Macromolecular Chemistry, Faculty of Science , Charles University , Hlavova 2030 , 128 40 Prague 2 , Czechia
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12
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Casanova-Morales N, Alavi Z, Wilson CAM, Zocchi G. Identifying Chaotropic and Kosmotropic Agents by Nanorheology. J Phys Chem B 2018. [DOI: 10.1021/acs.jpcb.7b12782] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nathalie Casanova-Morales
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380494, Chile
| | - Zahra Alavi
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380494, Chile
- Department of Physics, Loyola Marymount University, Los Angeles 90045, United States
| | - Christian A. M. Wilson
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380494, Chile
| | - Giovanni Zocchi
- Department of Physics and Astronomy, University of California—Los Angeles, Los Angeles, California 90095, United States
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13
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Billing BK, Mayank M, Agnihotri PK, Singh N. Development of pyrene-stacked carbon nanotube-based hybrid: measurement of NO3− ions using fluorescence spectroscopy. Analyst 2018; 143:3343-3352. [DOI: 10.1039/c8an00286j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
CNT@pyrene hybrid for fluorescent recognition of nitrate ions.
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Affiliation(s)
- Beant Kaur Billing
- Department of Mechanical Engineering
- Indian Institute of Technology Ropar
- Rupnagar
- India
| | - Mayank Mayank
- Department of Chemistry
- Indian Institute of Technology Ropar
- Rupnagar
- India
| | - Prabhat K. Agnihotri
- Department of Mechanical Engineering
- Indian Institute of Technology Ropar
- Rupnagar
- India
| | - Narinder Singh
- Department of Chemistry
- Indian Institute of Technology Ropar
- Rupnagar
- India
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14
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NaX solvation bonding dynamics:hydrogen bond and surface stress transition (X = HSO4, NO3, ClO4, SCN). J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.10.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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16
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Langton MJ, Serpell CJ, Beer PD. Anion Recognition in Water: Recent Advances from a Supramolecular and Macromolecular Perspective. Angew Chem Int Ed Engl 2016; 55:1974-87. [PMID: 26612067 PMCID: PMC4755225 DOI: 10.1002/anie.201506589] [Citation(s) in RCA: 313] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Indexed: 12/22/2022]
Abstract
The recognition of anions in water remains a key challenge in modern supramolecular chemistry, and is essential if proposed applications in biological, medical, and environmental arenas that typically require aqueous conditions are to be achieved. However, synthetic anion receptors that operate in water have, in general, been the exception rather than the norm to date. Nevertheless, a significant step change towards routinely conducting anion recognition in water has been achieved in the past few years, and this Review highlights these approaches, with particular focus on controlling and using the hydrophobic effect, as well as more exotic interactions such as C-H hydrogen bonding and halogen bonding. We also look beyond the field of small-molecule recognition into the macromolecular domain, covering recent advances in anion recognition based on biomolecules, polymers, and nanoparticles.
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Affiliation(s)
- Matthew J Langton
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | - Christopher J Serpell
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
- School of Physical Sciences, Ingram Building, University of Kent, Canterbury, Kent, CT2 7NH, UK.
| | - Paul D Beer
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
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17
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Langton MJ, Serpell CJ, Beer PD. Anionenerkennung in Wasser: aktuelle Fortschritte aus supramolekularer und makromolarer Sicht. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201506589] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Matthew J. Langton
- Chemistry Research Laboratory; Department of Chemistry; University of Oxford; Mansfield Road Oxford OX1 3TA Vereinigtes Königreich
| | - Christopher J. Serpell
- Chemistry Research Laboratory; Department of Chemistry; University of Oxford; Mansfield Road Oxford OX1 3TA Vereinigtes Königreich
- School of Physical Sciences, Ingram Building; University of Kent; Canterbury Kent CT2 7NH Vereinigtes Königreich
| | - Paul D. Beer
- Chemistry Research Laboratory; Department of Chemistry; University of Oxford; Mansfield Road Oxford OX1 3TA Vereinigtes Königreich
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Excess Partial Molar Absorptivity of Aqueous Solutions of KCl, KBr, CsCl and CsBr: Are There Three Universal Chromophores in the Excess Molar Absorptivity of the ν 2 + ν 3 Band of H2O for Aqueous Salt Solutions? J SOLUTION CHEM 2015. [DOI: 10.1007/s10953-015-0376-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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19
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Pérez-Fuentes L, Drummond C, Faraudo J, Bastos-González D. Anions make the difference: insights from the interaction of big cations and anions with poly(N-isopropylacrylamide) chains and microgels. SOFT MATTER 2015; 11:5077-5086. [PMID: 26027700 DOI: 10.1039/c5sm00750j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Minute concentrations of big hydrophobic ions have the ability to induce substantial effects in soft matter systems, including novel phases in lipid layers, giant charge inversion in colloids and nanostructuration in polymer surfaces in contact with water. The effects are so strong that the term "soft matter disruptors" was coined to describe their deep impact on interfaces, which goes far beyond that found by using the classical ions considered in lyotropic (Hofmeister) sequences. In these effects, solvation thermodynamics plays a fundamental role. Interestingly, it is possible to obtain big hydrophobic cations and anions with an almost identical size and structure (e.g. Ph4B(-), Ph4As(+)), which only differ in their central atom. Here we employ different techniques (Molecular Dynamics (MD) simulations, electrophoretic mobility and Atomic Force Microscopy (AFM)) to demonstrate the dramatic differences in the interaction of Ph4B(-) and Ph4As(+) with poly(N-isopropylacrylamide) (PNIPAM), a thermoresponsive polymer with expanded (well hydrated) and collapsed (poorly hydrated) states. Although both ions interact strongly with neutral PNIPAM chains and cationic or anionic PNIPAM microgels in the collapsed states, the effects of Ph4B(-) on PNIPAM are always substantially stronger than the effects of Ph4As(+). MD simulations predict that ion-PNIPAM free energy of interaction is four times larger for Ph4B(-) than for Ph4As(+). Electrokinetic and AFM experiments show that, acting as counter-ions, both ions are able to invert the charge of anionic or cationic PNIPAM microgels at minute concentrations, but the charge inversion due to Ph4B(-) is much larger than that obtained with Ph4As(+). Therefore, even for big ions of identical size, shape and valence, the affinity of anions and cations for interfaces is intrinsically different.
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Affiliation(s)
- Leonor Pérez-Fuentes
- Biocolloid and Fluid Physics Group, Department of Applied Physics, University of Granada, Av. Fuentenueva S/N, E-18071 Granada, Spain.
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Ball P, Hallsworth JE. Water structure and chaotropicity: their uses, abuses and biological implications. Phys Chem Chem Phys 2015; 17:8297-305. [PMID: 25628033 DOI: 10.1039/c4cp04564e] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The concept of "water structure" has been invoked to explain all manner of aqueous phenomena. Here we look at the origins of this tendency to understand solute hydration in terms of structural changes in bulk water, and consider the validity of one particular example: the classification of small solutes as chaotropic or kosmotropic, and the putative relation of this terminology to notions of structure-making and structure-breaking in the solvent. We doubt whether complex phenomena such as Hofmeister and osmolyte effects on macromolecules can be understood simply on the basis of a change in solvent structure. Rather, we argue that chaotropicity, if understood in the original sense, arises from the activities that solutes exert on macromolecular systems, as well as from deviations of solvation water from bulk-like behaviour. If applied judiciously, chaotropicity remains a potent, biologically pertinent parameter useful for classifying and understanding solution phenomena in all types of living system.
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Affiliation(s)
- Philip Ball
- 18 Hillcourt Road, East Dulwich, London SE22 0PE, UK.
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21
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Morita T, Miki K, Nitta A, Ohgi H, Westh P. Effects of constituent ions of a phosphonium-based ionic liquid on molecular organization of H2O as probed by 1-propanol: tetrabutylphosphonium and trifluoroacetate ions. Phys Chem Chem Phys 2015; 17:22170-8. [DOI: 10.1039/c5cp02329g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The phosphonium-based cation, [P4444]+, is significant amphiphile with strong hydrophobic and equally strong hydrophilic contributions.
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Affiliation(s)
- Takeshi Morita
- Graduate School of Advanced Integration Science
- Chiba University
- Chiba 263-8522
- Japan
| | - Kumiko Miki
- Department of Liberal Arts and Basic Sciences
- College of Industrial Technology
- Nihon University
- Narashino
- Japan
| | - Ayako Nitta
- Graduate School of Advanced Integration Science
- Chiba University
- Chiba 263-8522
- Japan
| | - Hiroyo Ohgi
- Graduate School of Advanced Integration Science
- Chiba University
- Chiba 263-8522
- Japan
| | - Peter Westh
- NSM Research for Functional Biomaterials
- Roskilde University
- Roskilde DK-4000
- Denmark
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