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A Distinctive Feature in the IR Spectra of Proton Disolvates [L2H+] and Polysolvates [(L2H+)·nL]: Unusual Strong Broadening of Some Absorption Bands of Ligands L Bound with H+ Full article

Journal PCCP: Physical Chemistry Chemical Physics
ISSN: 1463-9076 , E-ISSN: 1463-9084
Output data Year: 2000, Volume: 2, Number: 6, Pages: 1137-1145 Pages count : 9 DOI: 10.1039/a907815k
Tags benzyl thiocyanate; proton
Authors Stoyanov Eugenie S. 1
Affiliations
1 Boreskov Institute of Catalysis, Russian Academy of Sciences, Novosibirsk 630090, Russia

Abstract: An IR study of proton disolvates in organic solutions of L2H+FeCl4−, where L=tributyl phosphate (TBP), butyl acetate, diethyl ether, acetone and ethanol, or proton polysolvates of L2H+·nL·FeCl4− or (L′H+L)L′·FeCl4− (L=ethanol, L′=TBP) under the weak polarizing influence of FeCl4− anion on the cation led to the discovery of an unusual, very strong broadening of the absorption bands of the molecular groups of ligands L, which are directly bound with H+. These bands belong to (i) highly characteristic vibrations of double bonds P[double bond, length half m-dash]O(–H+), C[double bond, length half m-dash]O(–H+), etc., weakly mixed with the vibration of conjugated bonds, and (ii) strongly interacting group vibrations experiencing the influence of the proton. This effect is best exhibited in the IR spectra of proton solvates H+·nL with the positive charge located mainly on one O–H+–O group. The following explanation of this effect has been proposed. The potential function of the proton in the O–H+–O group is almost a single minimum with a flat bottom. Therefore, H+ is delocalized in a certain spatial interval between the oxygen atoms. As a result, the force constants of the bands of ligands L influenced by H+ change with the same frequencies as the proton migrates at the bottom of the flat potential minimum. This frequency may be comparable to those of some normal vibrations or exceed them. It has been shown that the same effect also takes place in the IR spectra of proton hydrates H5O2+· nL, where L=H2O or organic bases. The effect reported can form a basis for a new interpretation of the peculiarities in the IR spectra of proton hydrates.
Cite: Stoyanov E.S.
A Distinctive Feature in the IR Spectra of Proton Disolvates [L2H+] and Polysolvates [(L2H+)·nL]: Unusual Strong Broadening of Some Absorption Bands of Ligands L Bound with H+
PCCP: Physical Chemistry Chemical Physics. 2000. V.2. N6. P.1137-1145. DOI: 10.1039/a907815k WOS Scopus РИНЦ ANCAN OpenAlex
Dates:
Published print: Mar 15, 1999
Submitted: Sep 28, 1999
Accepted: Dec 17, 1999
Published online: Jan 9, 2000
Identifiers:
Web of science: WOS:000085733900006
Scopus: 2-s2.0-0034652826
Elibrary: 13351250
Chemical Abstracts: 2000:157511
Chemical Abstracts (print): 132:321618
OpenAlex: W2142203796
Citing:
DB Citing
Web of science 32
Scopus 31
Elibrary 32
OpenAlex 32
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