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Wei W, Chen X, Wang X. Nanopore Sensing Technique for Studying the Hofmeister Effect. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2200921. [PMID: 35484475 DOI: 10.1002/smll.202200921] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/22/2022] [Indexed: 06/14/2023]
Abstract
The nanopore sensing technique is an emerging method of detecting single molecules, and extensive research has gone into various fields, including nanopore sequencing and other applications of single-molecule studies. Recently, several researchers have explored the specific ion effects in nanopore channels, enabling a unique understanding of the Hofmeister effect at the single-molecule level. Herein, the recent advances of using nanopore sensing techniques are reviewed to study the Hofmeister effect and the physicochemical mechanism of this process is attempted. The challenges and goals are also discussed for the future in this field.
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Affiliation(s)
- Weichen Wei
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Xiaojuan Chen
- Department of Nanoengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Xuejiao Wang
- Fujian Provincial University Engineering Research Center of Industrial Biocatalysis, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, 350007, China
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2
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Aziz HR, Yao W, Jordan JH, Gibb BC. Dual Binding Modes of a Small Cavitand. Supramol Chem 2021. [DOI: 10.1080/10610278.2021.1987433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Hannah R. Aziz
- Department of Chemistry, Tulane University, New Orleans, LA, USA
| | - Wei Yao
- Department of Chemistry, Tulane University, New Orleans, LA, USA
| | - Jacobs H. Jordan
- Us Department of Agriculture, Agricultural Research Service Southern Regional Research Center, New Orleans, La, USA
| | - Bruce C. Gibb
- Department of Chemistry, Tulane University, New Orleans, LA, USA
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Yao W, Wang K, Ismaiel YA, Wang R, Cai X, Teeler M, Gibb BC. Electrostatic Potential Field Effects on Amine Macrocyclizations within Yoctoliter Spaces: Supramolecular Electron Withdrawing/Donating Groups. J Phys Chem B 2021; 125:9333-9340. [PMID: 34355901 PMCID: PMC8383300 DOI: 10.1021/acs.jpcb.1c05238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The
central role of Coulombic interactions in enzyme catalysis
has inspired multiple approaches to sculpting electrostatic potential
fields (EPFs) for controlling chemical reactivity, including ion gradients
in water microdroplets, the tips of STMs, and precisely engineered
crystals. These are powerful tools because EPFs can affect all reactions,
even those whose mechanisms do not involve formal charges. For some
time now, supramolecular chemists have become increasingly proficient
in using encapsulation to control stoichiometric and catalytic reactions.
However, the field has not taken advantage of the broad range of nanocontainers
available to systematically explore how EPFs can affect reactions
within their inner-spaces. With that idea in mind, previously, we
reported on how positively and negatively charged supramolecular capsules
can modulate the acidity and reactivity of thiol guests bound within
their inner, yoctoliter spaces (Cai, X.; Kataria, R.; Gibb, B. C. J. Am. Chem. Soc. 2020, 142, 8291–8298; Wang, K.; Cai, X.; Yao, W.; Tang, D.; Kataria,
R.; Ashbaugh, H. S.; Byers, L. D.; Gibb, B. C. J. Am. Chem.
Soc.2019, 141, 6740–6747).
Building on this, we report here on the cyclization of 14-bromotetradecan-1-amine
inside these yoctoliter containers. We examine the rate and activation
thermodynamics of cyclization (Eyring analysis), both in the absence
and presence of exogenous salts whose complementary ion can bind to
the outside of the capsule and hence attenuate its EPF. We find the
cyclization rates and activation thermodynamics in the two capsules
to be similar, but that for either capsule attenuation of the EPF
slows the reaction down considerably. We conclude the capsules behave
in a manner akin to covalently attached electron donating/withdrawing
groups in a substrate, with each capsule enforcing their own deviations
from the idealized SN2 mechanism by moving electron density
and charge in the activated complex and TS, and that the idealized
SN2 mechanism inside the theoretical neutral host is relatively
difficult because of the lack of solvation of the TS.
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Affiliation(s)
- Wei Yao
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Kaiyu Wang
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Yahya A Ismaiel
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Ruiqing Wang
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Xiaoyang Cai
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Mary Teeler
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Bruce C Gibb
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
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Cai X, Kataria R, Gibb BC. Intrinsic and Extrinsic Control of the p Ka of Thiol Guests inside Yoctoliter Containers. J Am Chem Soc 2020; 142:8291-8298. [PMID: 32271561 DOI: 10.1021/jacs.0c00907] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Despite decades of research, there are still many open questions surrounding the mechanisms by which enzymes catalyze reactions. Understanding all the noncovalent forces involved has the potential to allow de novo catalysis design, and as a step toward this, understanding how to control the charge state of ionizable groups represents a powerful yet straightforward approach to probing complex systems. Here we utilize supramolecular capsules assembled via the hydrophobic effect to encapsulate guests and control their acidity. We find that the greatest influence on the acidity of bound guests is the location of the acidic group within the yoctoliter space. However, the nature of the electrostatic field generated by the (remote) charged solubilizing groups also plays a significant role in acidity, as does counterion complexation to the outer surfaces of the capsules. Taken together, these results suggest new ways by which to affect reactions in confined spaces.
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Affiliation(s)
- Xiaoyang Cai
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Rhea Kataria
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Bruce C Gibb
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
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Abstract
Dynamic light scattering (DLS) is a useful tool for the study of the solution-based behavior of colloids and molecular assemblies. The aim of this methods paper is to provide perspective on how this technique can be used by supramolecular chemists. As this technique is not extensively used within the field, we also provide a historical background of its development, summarize data interpretation and the strengths and limitations of the technique, and provide a perspective on some of the important features for supramolecular chemists that can be found in an instrument.
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Affiliation(s)
- Anthony Wishard
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA
| | - Bruce C Gibb
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA
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Jordan JH, Wishard A, Mague JT, Gibb BC. Binding Properties and Supramolecular Polymerization of a Water-Soluble Resorcin[4]arene. Org Chem Front 2019; 6:1236-1243. [PMID: 31772734 PMCID: PMC6879061 DOI: 10.1039/c9qo00182d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Controlling the self-assembly of molecules in water is difficult because the small size, polarity, and hydrogen bond donating and accepting properties of water attenuate most non-covalent interactions. Here we describe how resorcinarene 1, with pyridinium pendent groups, assembles in water to form head-to-tail assemblies. These small supramolecular polymers form because they offer greater stabilization than any latent head-to-head assembly of resorcinarenes to form dimeric (or hexameric) containers. Instead, the resorcinarene bowl - particularly if negatively charged - is a good host for the pyridinium pendent groups of a second resorcinarene. Alternatively, resorcinarene 1 is also a good host for complexing anions and cations of any added salt. In combination therefore, host 1 possesses a rich repertoire of supramolecular properties that is dependent on the ionic strength and the nature of salts, pH, and the concentration of the host. These findings provide new information about controlling the self-assembly of resorcinarenes in water.
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Affiliation(s)
- Jacobs H Jordan
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA,
| | - Anthony Wishard
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA,
| | - Joel T Mague
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA,
| | - Bruce C Gibb
- Department of Chemistry, Tulane University, New Orleans, LA 70118, USA,
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Wang K, Cai X, Yao W, Tang D, Kataria R, Ashbaugh HS, Byers LD, Gibb BC. Electrostatic Control of Macrocyclization Reactions within Nanospaces. J Am Chem Soc 2019; 141:6740-6747. [DOI: 10.1021/jacs.9b02287] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Kaiya Wang
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Xiaoyang Cai
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Wei Yao
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Du Tang
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Rhea Kataria
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Henry S. Ashbaugh
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
| | - Larry D Byers
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Bruce C. Gibb
- Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
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Abstract
GEST NMR provides dynamic information on host–guest systems. It allows signal amplification of low concentrated complexes, detection of intermolecular interactions and quantification of guest exchange rates.
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Affiliation(s)
- Liat Avram
- Faculty of Chemistry
- Weizmann Institute of Science
- 7610001 Rehovot
- Israel
| | - Amnon Bar-Shir
- Faculty of Chemistry
- Weizmann Institute of Science
- 7610001 Rehovot
- Israel
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