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Title: Characterization of selective binding of alkali cations with carboxylate by x-ray absorption spectroscopy of liquid microjets

Abstract

We describe an approach for characterizing selective binding between oppositely charged ionic functional groups under biologically relevant conditions. Relative shifts in K-shell x-ray absorption spectra of aqueous cations and carboxylate anions indicate the corresponding binding strengths via perturbations of carbonyl antibonding orbitals. XAS spectra measured for aqueous formate and acetate solutions containing lithium, sodium, and potassium cations reveal monotonically stronger binding of the lighter metals, supporting recent results from simulations and other experiments. The carbon K-edge spectra of the acetate carbonyl feature centered near 290 eV clearly indicate a preferential interaction of sodium versus potassium, which was less apparent with formate. These results are in accord with the Law of Matching Water Affinities, relating relative hydration strengths of ions to their respective tendencies to form contact ion pairs. Density functional theory calculations of K-shell spectra support the experimental findings.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Chemical Sciences Division
OSTI Identifier:
936730
Report Number(s):
LBNL-894E
Journal ID: ISSN 0027-8424; PNASA6; TRN: US0805684
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
PNAS
Additional Journal Information:
Journal Volume: 105; Journal Issue: 19; Related Information: Journal Publication Date: May 13, 2008; Journal ID: ISSN 0027-8424
Country of Publication:
United States
Language:
English
Subject:
75; ABSORPTION SPECTRA; ABSORPTION SPECTROSCOPY; ACETATES; ANIONS; CARBON; CARBONYLS; CATIONS; FORMATES; FUNCTIONALS; HYDRATION; ION PAIRS; K SHELL; LITHIUM; POTASSIUM; SODIUM; SPECTRA; WATER

Citation Formats

Saykally, Richard J, Uejio, Janel S, Schwartz, Craig P, Duffin, Andrew M, Drisdell, Walter S, Cohen, Ronald C, and Saykally, Richard J. Characterization of selective binding of alkali cations with carboxylate by x-ray absorption spectroscopy of liquid microjets. United States: N. p., 2008. Web.
Saykally, Richard J, Uejio, Janel S, Schwartz, Craig P, Duffin, Andrew M, Drisdell, Walter S, Cohen, Ronald C, & Saykally, Richard J. Characterization of selective binding of alkali cations with carboxylate by x-ray absorption spectroscopy of liquid microjets. United States.
Saykally, Richard J, Uejio, Janel S, Schwartz, Craig P, Duffin, Andrew M, Drisdell, Walter S, Cohen, Ronald C, and Saykally, Richard J. Tue . "Characterization of selective binding of alkali cations with carboxylate by x-ray absorption spectroscopy of liquid microjets". United States. https://www.osti.gov/servlets/purl/936730.
@article{osti_936730,
title = {Characterization of selective binding of alkali cations with carboxylate by x-ray absorption spectroscopy of liquid microjets},
author = {Saykally, Richard J and Uejio, Janel S and Schwartz, Craig P and Duffin, Andrew M and Drisdell, Walter S and Cohen, Ronald C and Saykally, Richard J},
abstractNote = {We describe an approach for characterizing selective binding between oppositely charged ionic functional groups under biologically relevant conditions. Relative shifts in K-shell x-ray absorption spectra of aqueous cations and carboxylate anions indicate the corresponding binding strengths via perturbations of carbonyl antibonding orbitals. XAS spectra measured for aqueous formate and acetate solutions containing lithium, sodium, and potassium cations reveal monotonically stronger binding of the lighter metals, supporting recent results from simulations and other experiments. The carbon K-edge spectra of the acetate carbonyl feature centered near 290 eV clearly indicate a preferential interaction of sodium versus potassium, which was less apparent with formate. These results are in accord with the Law of Matching Water Affinities, relating relative hydration strengths of ions to their respective tendencies to form contact ion pairs. Density functional theory calculations of K-shell spectra support the experimental findings.},
doi = {},
url = {https://www.osti.gov/biblio/936730}, journal = {PNAS},
issn = {0027-8424},
number = 19,
volume = 105,
place = {United States},
year = {2008},
month = {1}
}