Document Detail


Theoretical studies on the electronic structure, charge distribution and vibrational spectra of diglyme-M(+)-AsF(6)(-) (M=Li, Na, K).
MedLine Citation:
PMID:  18436474     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Electronic structure and the vibrational spectra of CH(3)(OCH(2)CH(2))(2)OCH(3)-M(+)-AsF(6)(-) (M=Li, Na, K) have been obtained using the density functional theory. Lithium ion exhibits a pentavalent coordination via 3 oxygens from diglyme and two fluorines of AsF(6)(-) whereas Na(+) and K(+) exhibit coordinate number 6 with 3 fluorines of the anion binding to alkali metal in these complexes. Analysis of calculated spectra reveal that the CH(2) wag (840-1120 cm(-1)) vibrations in the complex are sensitive to metal ion coordination. A frequency downshift relative to the free anion has been predicted for the vibrations of AsF(6)(-) anion when the fluorines are directly bonded (denoted by F) to metal ion. Consequent reorganization of electron density in the complex engenders a frequency shift in the opposite direction for As-F vibrations wherein the fluorine atoms are not coordinating to the alkali metal ion. An approach based on the molecular electron density topography coupled with the difference electron density map explains the direction of the frequency shifts of C-O-C and the As-F stretchings compared to those of free diglyme or AsF(6) anion. A new method, which includes the color-mapping function for the difference molecular electron density (MED), superimposed on the bond critical points in MED topography has been suggested to explain the direction of the frequency shifts in a single attempt.
Authors:
Rahul V Pinjari; Kaustubh A Joshi; Shridhar P Gejji
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-03-14
Journal Detail:
Title:  Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy     Volume:  71     ISSN:  1386-1425     ISO Abbreviation:  Spectrochim Acta A Mol Biomol Spectrosc     Publication Date:  2008 Dec 
Date Detail:
Created Date:  2009-02-25     Completed Date:  2009-03-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9602533     Medline TA:  Spectrochim Acta A Mol Biomol Spectrosc     Country:  England    
Other Details:
Languages:  eng     Pagination:  1056-62     Citation Subset:  IM    
Affiliation:
Department of Chemistry, University of Pune, Ganeshkhind 411007, India.
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MeSH Terms
Descriptor/Qualifier:
Arsenicals / chemistry*
Electric Conductivity
Electrochemistry
Electrolytes / chemistry
Ethylene Glycols / chemistry*
Lithium / chemistry
Methyl Ethers / chemistry*
Models, Molecular
Molecular Structure
Potassium / chemistry
Sodium / chemistry
Spectrum Analysis
Chemical
Reg. No./Substance:
0/Arsenicals; 0/Electrolytes; 0/Ethylene Glycols; 0/Methyl Ethers; 111-96-6/diglyme; 7439-93-2/Lithium; 7440-09-7/Potassium; 7440-23-5/Sodium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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