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Rezaei-Ghaleh N, Agudo-Canalejo J, Griesinger C, Golestanian R. Response to Comment on "Following Molecular Mobility during Chemical Reactions: No Evidence for Active Propulsion" and "Molecular Diffusivity of Click Reaction Components: The Diffusion Enhancement Question". J Am Chem Soc 2022; 144:13441-13445. [PMID: 35919985 PMCID: PMC9354245 DOI: 10.1021/jacs.2c02850] [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
In their Comment
(DOI: 10.1021/jacs.2c02965) on two related publications by our
group (J. Am. Chem.
Soc.2022, 144, 1380–1388;
DOI: 10.1021/jacs.1c11754) and another (J. Am. Chem.
Soc.2021, 143, 20884–20890;
DOI: 10.1021/jacs.1c09455), Huang and Granick refer to the
diffusion NMR measurements of molecules during a copper-catalyzed
azide–alkyne cycloaddition (CuAAC) “click” reaction.
Here we respond to their comments and maintain that no measurable
diffusion enhancement was observed during the reaction. We expand
on the physical arguments presented in our original JACS Article regarding the appropriate reference state for the diffusion
coefficient and present new data showing that the use of other reference
states, as suggested by Huang and Granick, will still support our
conclusion that the two reactants and one product of the CuAAC reaction
do not exhibit boosted mobility during the reaction.
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Affiliation(s)
- Nasrollah Rezaei-Ghaleh
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, D-37077 Göttingen, Germany.,Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany
| | - Jaime Agudo-Canalejo
- Department of Living Matter Physics, Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, D-37077 Göttingen, Germany
| | - Christian Griesinger
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11, D-37077 Göttingen, Germany
| | - Ramin Golestanian
- Department of Living Matter Physics, Max Planck Institute for Dynamics and Self-Organization, Am Faßberg 17, D-37077 Göttingen, Germany.,Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
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Huang T, Granick S. Comment on “Following Molecular Mobility during Chemical Reactions: No Evidence for Active Propulsion” and “Molecular Diffusivity of Click Reaction Components: The Diffusion Enhancement Question”. J Am Chem Soc 2022; 144:13431-13435. [DOI: 10.1021/jacs.2c02965] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Tian Huang
- Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, South Korea
| | - Steve Granick
- Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, South Korea
- Departments of Chemistry and Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea
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Fillbrook LL, Günther JP, Majer G, O'Leary DJ, Price WS, Van Ryswyk H, Fischer P, Beves JE. Response to Comment on "Following Molecular Mobility during Chemical Reactions: No Evidence for Active Propulsion" and "Molecular Diffusivity of Click Reaction Components: The Diffusion Enhancement Question". J Am Chem Soc 2022; 144:13436-13440. [PMID: 35919987 DOI: 10.1021/jacs.2c02830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In their Comment (DOI: 10.1021/jacs.2c02965) on two related publications by our groups (J. Am. Chem. Soc. 2021, 143, 20884-20890; DOI: 10.1021/jacs.1c09455) and another (J. Am. Chem. Soc. 2022, 144, 1380-1388; DOI: 10.1021/jacs.1c11754), Huang and Granick discuss the diffusion NMR measurements of molecules during a copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" reaction. Here we respond to these comments and maintain that no diffusion enhancement was observed for any species during the reaction. We show that the relaxation agent does not interfere with the CuAAC reaction kinetics nor the diffusion of the molecules involved. Similarly, the gradient pulse length and diffusion time do not affect the diffusion coefficients. Peak overlap was completely removed in our study with the use of hydrazine as the reducing agent. The steady-state assumption does not hold for these diffusion measurements that take several minutes, which is the reason monotonic gradient orders are not suitable. Finally, we discuss the other reactions where similar changes in diffusion have been claimed. Our conclusions are fully supported by the results represented in our original JACS Article and the corresponding Supporting Information.
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Affiliation(s)
| | - Jan-Philipp Günther
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Günter Majer
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany
| | - Daniel J O'Leary
- Department of Chemistry, Pomona College, 645 North College Avenue, Claremont, California 91711, United States
| | - William S Price
- Nanoscale Group, School of Science, Western Sydney University, Penrith, NSW 2751, Australia
| | - Hal Van Ryswyk
- Department of Chemistry, Harvey Mudd College, 301 Platt Boulevard, Claremont, California 91711, United States
| | - Peer Fischer
- Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany.,Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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Rezaei-Ghaleh N, Agudo-Canalejo J, Griesinger C, Golestanian R. Molecular Diffusivity of Click Reaction Components: The Diffusion Enhancement Question. J Am Chem Soc 2022; 144:1380-1388. [PMID: 35078321 PMCID: PMC8796239 DOI: 10.1021/jacs.1c11754] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Indexed: 02/06/2023]
Abstract
Micrometer-sized objects are widely known to exhibit chemically driven motility in systems away from equilibrium. Experimental observation of reaction-induced motility or enhancement in diffusivity at the much shorter length scale of small molecules is, however, still a matter of debate. Here, we investigate the molecular diffusivity of reactants, catalyst, and product of a model reaction, the copper-catalyzed azide-alkyne cycloaddition click reaction, and develop new NMR diffusion approaches that allow the probing of reaction-induced diffusion enhancement in nanosized molecular systems with higher accuracy than the state of the art. Following two different approaches that enable the accounting of time-dependent concentration changes during NMR experiments, we closely monitored the diffusion coefficient of reaction components during the reaction. The reaction components showed distinct changes in the diffusivity: while the two reactants underwent a time-dependent decrease in their diffusivity, the diffusion coefficient of the product gradually increased and the catalyst showed only slight diffusion enhancement within the range expected for reaction-induced sample heating. The decrease in diffusion coefficient of the alkyne, one of the two reactants of click reaction, was not reproduced during its copper coordination when the second reactant, azide, was absent. Our results do not support the catalysis-induced diffusion enhancement of the components of the click reaction and, instead, point to the role of a relatively large intermediate species within the reaction cycle with diffusivity lower than that of both the reactants and product molecule.
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Affiliation(s)
- Nasrollah Rezaei-Ghaleh
- Department
of NMR-Based Structural Biology, Max Planck
Institute for Biophysical Chemistry, Am Faßberg 11, D-37077 Göttingen, Germany
- Institut
für Physikalische Biologie, Heinrich-Heine-Universität
Düsseldorf, Universitätsstraße
1, D-40225 Düsseldorf, Germany
| | - Jaime Agudo-Canalejo
- Department
of Living Matter Physics, Max Planck Institute
for Dynamics and Self-Organization, Am Faßberg 17, D-37077 Göttingen, Germany
| | - Christian Griesinger
- Department
of NMR-Based Structural Biology, Max Planck
Institute for Biophysical Chemistry, Am Faßberg 11, D-37077 Göttingen, Germany
| | - Ramin Golestanian
- Department
of Living Matter Physics, Max Planck Institute
for Dynamics and Self-Organization, Am Faßberg 17, D-37077 Göttingen, Germany
- Rudolf
Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
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Fillbrook LL, Günther JP, Majer G, O'Leary DJ, Price WS, Van Ryswyk H, Fischer P, Beves JE. Following Molecular Mobility during Chemical Reactions: No Evidence for Active Propulsion. J Am Chem Soc 2021; 143:20884-20890. [PMID: 34856103 DOI: 10.1021/jacs.1c09455] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The reported changes in self-diffusion of small molecules during reactions have been attributed to "boosted mobility". We demonstrate the critical role of changing concentrations of paramagnetic ions on nuclear magnetic resonance (NMR) signal intensities, which led to erroneous measurements of diffusion coefficients. We present simple methods to overcome this problem. The use of shuffled gradient amplitudes allows accurate diffusion NMR measurements, even with time-dependent relaxation rates caused by changing concentrations of paramagnetic ions. The addition of a paramagnetic relaxation agent allows accurate determination of both diffusion coefficients and reaction kinetics during a single experiment. We analyze a copper-catalyzed azide-alkyne cycloaddition "click" reaction, for which boosted mobility has been claimed. With our methods, we accurately measure the diffusive behavior of the solvent, starting materials, and product and find no global increase in diffusion coefficients during the reaction. We overcome NMR signal overlap using an alternative reducing agent to improve the accuracy of the diffusion measurements. The alkyne reactant diffuses slower as the reaction proceeds due to binding to the copper catalyst during the catalytic cycle. The formation of this intermediate was confirmed by complementary NMR techniques and density functional theory calculations. Our work calls into question recent claims that molecules actively propel or swim during reactions and establishes that time-resolved diffusion NMR measurements can provide valuable insight into reaction mechanisms.
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Affiliation(s)
| | - Jan-Philipp Günther
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany.,Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Günter Majer
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany
| | - Daniel J O'Leary
- Department of Chemistry, Pomona College, 645 North College Ave., Claremont, California 91711, United States
| | - William S Price
- Nanoscale Group, School of Science, Western Sydney University, Penrith, NSW 2751, Australia
| | - Hal Van Ryswyk
- Department of Chemistry, Harvey Mudd College, 301 Platt Blvd., Claremont, California 91711, United States
| | - Peer Fischer
- Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany.,Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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Huang T, Li B, Wang H, Granick S. Molecules, the Ultimate Nanomotor: Linking Chemical Reaction Intermediates to their Molecular Diffusivity. ACS NANO 2021; 15:14947-14953. [PMID: 34523903 DOI: 10.1021/acsnano.1c05168] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The intellectual community focused on nanomotors has recently become interested in extending these concepts to individual molecules. Here, we study a chemical reaction according to whose mechanism some intermediate species should speed up while others slow down in predictable ways, if the nanomotor hypothesis of boosted diffusion holds. Accordingly, we scrutinize the absolute diffusion coefficient (D) during intermediate steps of the catalytic cycle for the CuAAC reaction (copper-catalyzed azide-alkyne cycloaddition click reaction), using proton pulsed field-gradient nuclear magnetic resonance to discriminate between the diffusion of various reaction intermediates. We observe time-dependent diffusion that is enhanced for some intermediate molecular species and depressed for those whose size increases owing to complex formation. These findings point to the failure of the conventional Stokes-Einstein equation to fully explain diffusivity during chemical reaction. Without attempting a firm explanation, this paper highlights aspects of the physics of chemical reactions that are imperfectly understood and presents systematic data that can be used to assess hypotheses.
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Affiliation(s)
- Tian Huang
- Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, South Korea
| | - Bo Li
- Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, South Korea
| | - Huan Wang
- College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, People's Republic of China
| | - Steve Granick
- Center for Soft and Living Matter, Institute for Basic Science (IBS), Ulsan 44919, South Korea
- Departments of Chemistry and Physics, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea
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