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Short-Range Cooperative Slow-down of Water Solvation Dynamics Around SO(4)(2–)–Mg(2+) Ion Pairs

[Image: see text] The presence of ions affects the structure and dynamics of water on a multitude of length and time scales. In this context, pairs of Mg(2+) and SO(4)(2–) ions in water constitute a prototypical system for which conflicting pictures of hydration geometries and dynamics have been rep...

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Autores principales: Kundu, Achintya, Mamatkulov, Shavkat I., Brünig, Florian N., Bonthuis, Douwe Jan, Netz, Roland R., Elsaesser, Thomas, Fingerhut, Benjamin P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9706802/
https://www.ncbi.nlm.nih.gov/pubmed/36465835
http://dx.doi.org/10.1021/acsphyschemau.2c00034
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author Kundu, Achintya
Mamatkulov, Shavkat I.
Brünig, Florian N.
Bonthuis, Douwe Jan
Netz, Roland R.
Elsaesser, Thomas
Fingerhut, Benjamin P.
author_facet Kundu, Achintya
Mamatkulov, Shavkat I.
Brünig, Florian N.
Bonthuis, Douwe Jan
Netz, Roland R.
Elsaesser, Thomas
Fingerhut, Benjamin P.
author_sort Kundu, Achintya
collection PubMed
description [Image: see text] The presence of ions affects the structure and dynamics of water on a multitude of length and time scales. In this context, pairs of Mg(2+) and SO(4)(2–) ions in water constitute a prototypical system for which conflicting pictures of hydration geometries and dynamics have been reported. Key issues are the molecular pair and solvation shell geometries, the spatial range of electric interactions, and their impact on solvation dynamics. Here, we introduce asymmetric SO(4)(2–) stretching vibrations as new and most specific local probes of solvation dynamics that allow to access ion hydration dynamics at the dilute concentration (0.2 M) of a native electrolyte environment. Highly sensitive heterodyne 2D-IR spectroscopy in the fingerprint region of the SO(4)(2–) ions around 1100 cm(–1) reveals a specific slow-down of solvation dynamics for hydrated MgSO(4) and for Na(2)SO(4) in the presence of Mg(2+) ions, which manifests as a retardation of spectral diffusion compared to aqueous Na(2)SO(4) solutions in the absence of Mg(2+) ions. Extensive molecular dynamics and density functional theory QM/MM simulations provide a microscopic view of the observed ultrafast dephasing and hydration dynamics. They suggest a molecular picture where the slow-down of hydration dynamics arises from the structural peculiarities of solvent-shared SO(4)(2–)–Mg(2+) ion pairs.
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spelling pubmed-97068022022-11-30 Short-Range Cooperative Slow-down of Water Solvation Dynamics Around SO(4)(2–)–Mg(2+) Ion Pairs Kundu, Achintya Mamatkulov, Shavkat I. Brünig, Florian N. Bonthuis, Douwe Jan Netz, Roland R. Elsaesser, Thomas Fingerhut, Benjamin P. ACS Phys Chem Au [Image: see text] The presence of ions affects the structure and dynamics of water on a multitude of length and time scales. In this context, pairs of Mg(2+) and SO(4)(2–) ions in water constitute a prototypical system for which conflicting pictures of hydration geometries and dynamics have been reported. Key issues are the molecular pair and solvation shell geometries, the spatial range of electric interactions, and their impact on solvation dynamics. Here, we introduce asymmetric SO(4)(2–) stretching vibrations as new and most specific local probes of solvation dynamics that allow to access ion hydration dynamics at the dilute concentration (0.2 M) of a native electrolyte environment. Highly sensitive heterodyne 2D-IR spectroscopy in the fingerprint region of the SO(4)(2–) ions around 1100 cm(–1) reveals a specific slow-down of solvation dynamics for hydrated MgSO(4) and for Na(2)SO(4) in the presence of Mg(2+) ions, which manifests as a retardation of spectral diffusion compared to aqueous Na(2)SO(4) solutions in the absence of Mg(2+) ions. Extensive molecular dynamics and density functional theory QM/MM simulations provide a microscopic view of the observed ultrafast dephasing and hydration dynamics. They suggest a molecular picture where the slow-down of hydration dynamics arises from the structural peculiarities of solvent-shared SO(4)(2–)–Mg(2+) ion pairs. American Chemical Society 2022-10-08 /pmc/articles/PMC9706802/ /pubmed/36465835 http://dx.doi.org/10.1021/acsphyschemau.2c00034 Text en © 2022 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by-nc-nd/4.0/Permits non-commercial access and re-use, provided that author attribution and integrity are maintained; but does not permit creation of adaptations or other derivative works (https://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Kundu, Achintya
Mamatkulov, Shavkat I.
Brünig, Florian N.
Bonthuis, Douwe Jan
Netz, Roland R.
Elsaesser, Thomas
Fingerhut, Benjamin P.
Short-Range Cooperative Slow-down of Water Solvation Dynamics Around SO(4)(2–)–Mg(2+) Ion Pairs
title Short-Range Cooperative Slow-down of Water Solvation Dynamics Around SO(4)(2–)–Mg(2+) Ion Pairs
title_full Short-Range Cooperative Slow-down of Water Solvation Dynamics Around SO(4)(2–)–Mg(2+) Ion Pairs
title_fullStr Short-Range Cooperative Slow-down of Water Solvation Dynamics Around SO(4)(2–)–Mg(2+) Ion Pairs
title_full_unstemmed Short-Range Cooperative Slow-down of Water Solvation Dynamics Around SO(4)(2–)–Mg(2+) Ion Pairs
title_short Short-Range Cooperative Slow-down of Water Solvation Dynamics Around SO(4)(2–)–Mg(2+) Ion Pairs
title_sort short-range cooperative slow-down of water solvation dynamics around so(4)(2–)–mg(2+) ion pairs
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9706802/
https://www.ncbi.nlm.nih.gov/pubmed/36465835
http://dx.doi.org/10.1021/acsphyschemau.2c00034
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