Role of the Orbitally Degenerate Mn(III) Ions in the Single-Molecule Magnet Behavior of the Cyanide Cluster {[MnII(tmphen)2]3[MnIII(CN)6]2
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- 作者：Andrei V. Palii ; Sergei M. Ostrovsky ; Sophia I. Klokishner ; Boris S. Tsukerblat ; Curtis P. Berlinguette ; Kim R. Dunbar ; and José ; Ramó ; n Galá ; n-Mascaró ; s
- 刊名：Journal of the American Chemical Society
- 出版年：2004
- 出版时间：December 29, 2004
- 年：2004
- 卷：126
- 期：51
- 页码：16860 - 16867
- 全文大小：164K
- 年卷期：v.126,no.51(December 29, 2004)
- ISSN：1520-5126
文摘
We report a new theoretical model that accounts for the unusual magnetic properties of thecyanide cluster {[MnII(tmphen)2]3[MnIII(CN)6]2} (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline). Themodel takes into account (1) the spin-orbit interaction, (2) the trigonal component of the crystal field actingon the ground-state cubic 3T1(
) terms of the apical Mn(III) ions, and (3) the isotropic contribution to theexchange interaction between Mn(III) and Mn(II) ions. The ground state of the cluster was shown to be thestate with the total angular momentum projection 
mages/entities/verbar.gif">MJmages/entities/verbar.gif"> = 15/2; the energies of the low-lying levels obtainedfrom this treatment increase with decreasing mages/entities/verbar.gif">MJmages/entities/verbar.gif"> values, a situation that leads to a barrier for the reversalof magnetization (Ueff mages/entities/ap.gif"> 30 cm-1). The new model explains the recently discovered single-molecule magnetbehavior of the {[MnII(tmphen)2]3[MnIII(CN)6]2} in contrast to the traditional approach that takes into accountonly the ground-state spin (S) and a negative zero-field splitting parameter (DS < 0).
) terms of the apical Mn(III) ions, and (3) the isotropic contribution to theexchange interaction between Mn(III) and Mn(II) ions. The ground state of the cluster was shown to be thestate with the total angular momentum projection