Reference : Slow Magnetic Relaxation in a Series of Non-Heme Trigonal Pyramidal Iron(II) Pyrrolid...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Chemistry
http://hdl.handle.net/2268/81709
Slow Magnetic Relaxation in a Series of Non-Heme Trigonal Pyramidal Iron(II) Pyrrolide Complexes
English
Harmann, Hill E [Berkeley University of California - UC Berkeley > Chemistry > > >]
Harris, T David [Berkeley University of California - UC Berkeley > Chemistry > > >]
Freedman, Danna E [Berkeley University of California - UC Berkeley > Chemistry > > >]
Fong, H. [Berkeley University of California - UC Berkeley > Chemistry > > >]
Chang, A. [Berkeley University of California - UC Berkeley > Chemistry > > >]
Rinehart, Jeffrey D [Berkeley University of California - UC Berkeley > Chemistry > > >]
Grandjean, Fernande mailto [Université de Liège - ULg > Département de physique > Département de physique >]
Ozarowski, Andrew [National Magnet Laboratory Florida > > > >]
Long, Gary J mailto [Missouri University of Science and Technology > Chemistry > > > >]
Long, Jeffrey R [Berkeley University of California - UC Berkeley > Chemistry > > >]
Chang, Christopher [University of California-Berkeley > Chemist6ry > > >]
2010
Journal of the American Chemical Society
American Chemical Society
132
18115
Yes (verified by ORBi)
International
0002-7863
1520-5126
Washington
DC
[en] Crystal structure ; magnetic properties ; Mossbauer spectroscopy
[en] We present a family of novel non-heme trigonal pyramidal iron(II) complexes supported by tris(pyrrolyl-α-methyl)amine ligands of the form [M(solv)n][(tpaR)Fe] (M = Na, R = tert-butyl (1), phenyl (4); M = K, R = mesityl (2), 2,4,6-triisopropylphenyl (3), 2,6-difluorophenyl (5)) and their characterization by X-ray crystallography, cyclic voltammetry, and Mössbauer spectroscopy. Expanding on the initial discovery of slow magnetic relaxation in the recently reported mesityl derivative 2, we report the static and dynamic magnetic properties of a homologous series of high-spin mononuclear iron(II) complexes that exhibit this intriguing behavior. Magnetization experiments reveal large, negative zero-field splitting parameters of D = −48, −40, −36, −26 and −6.2 cm−1 for 1-5, respectively. In the case of 2,6-difluorophenyl 5, high-field EPR experiments provide an independent determination of the zero-field splitting parameters (D = −4.397(9)) that are in reasonable agreement with the magnetization data. Ac susceptibility measurements indicate field-dependent, thermally-activated spin reversal barriers in complexes 1, 2 and 4 of Ueff = 60, 42 and 25 cm−1, respectively. In the case of 1, this value constitutes the highest spin-reversal barrier observed for a mononuclear transition metal complex, a property that has broad implications for the design of molecules that can potentially store and process magnetic information.
Researchers
http://hdl.handle.net/2268/81709

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