Document Detail

Slow magnetic relaxation in a high-spin iron(II) complex.
MedLine Citation:
PMID:  20055389     Owner:  NLM     Status:  MEDLINE    
Slow magnetic relaxation is observed for [(tpa(Mes))Fe](-), a trigonal pyramidal complex of high-spin iron(II), providing the first example of a mononuclear transition metal complex that behaves as a single-molecule magnet. Dc magnetic susceptibility and magnetization measurements reveal a strong uniaxial magnetic anisotropy (D = -39.6 cm(-1)) acting on the S = 2 ground state of the molecule. Ac magnetic susceptibility measurements indicate the absence of slow relaxation under zero applied dc field as a result of quantum tunneling of the magnetization. Application of a 1500 Oe dc field initiates slow magnetic relaxation, which follows a thermally activated tunneling mechanism at high temperature to give an effective spin-reversal barrier of U(eff) = 42 cm(-1) and follows a temperature-independent tunneling mechanism at low temperature. In addition, the magnetic relaxation time shows a pronounced dc-field dependence, with a maximum occurring at approximately 1500 Oe.
Danna E Freedman; W Hill Harman; T David Harris; Gary J Long; Christopher J Chang; Jeffrey R Long
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of the American Chemical Society     Volume:  132     ISSN:  1520-5126     ISO Abbreviation:  J. Am. Chem. Soc.     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-01-27     Completed Date:  2010-04-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7503056     Medline TA:  J Am Chem Soc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1224-5     Citation Subset:  IM    
Department of Chemistry and Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA.
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MeSH Terms
Iron Compounds / chemistry*
Models, Molecular
Grant Support
//Howard Hughes Medical Institute
Reg. No./Substance:
0/Iron Compounds

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