Trinuclear {M1}CN{M2}2 complexes (M1 = Cr(III), Fe(III), Co(III); M2 = Cu(II), Ni(II), Mn(II)). Are single molecule magnets predictable?
Trinuclear {M1}CN{M2}2 complexes (M1 = Cr(III), Fe(III), Co(III); M2 = Cu(II), Ni(II), Mn(II)). Are single molecule magnets predictable?
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DOI：
10.1021/ic800556c
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发表时间：
2008-08
影响因子：
4.6
通讯作者：
M. Atanasov;C. Busche;P. Comba;F. El Hallak;Bodo Martin;G. Rajaraman;J. van Slageren;H. Wadepohl
中科院分区：
文献类型：
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作者：
M. Atanasov;C. Busche;P. Comba;F. El Hallak;Bodo Martin;G. Rajaraman;J. van Slageren;H. Wadepohl
六氰基金属盐 K3[M(1)(CN)6] (M(1) = Cr(III)、Fe(III)、Co(III)) 与双吡啶配合物 [M(2)(L(1))(X)](n+) 和 [M(2)(L(2))(X)](n+) 的反应 (M(2) = Mn(II)、Ni(II)、Cu(II)；L(1) = 3-甲基-9-氧代-2,4-二-(2-吡啶基)-7-(2-吡啶基甲基)-3,7-二氮杂双环[3.3.1]壬烷-1,5-二甲酸二甲酯L(2) = 3-甲基-9-氧代-7-(2-吡啶基甲基)-2,4-二-(2-喹啉基)-3,7-二氮杂双环[3.3.1]壬烷-1,5-二甲酸二甲酯；X=阴离子或溶剂)在水-甲醇混合物中得到三核络合物，其双吡啶封端的二价金属中心围绕六氰基金属盐呈顺式或反式排列。报道了该配合物家族的五个成员（cis-Fe[CuL(2)]2、trans-Fe[CuL(1)]2、cis-Co[CuL(2)]2、trans-Cr[MnL(1)]2、trans-Fe[MnL(1)]2）的X射线结构分析以及整个系列的磁性数据。使用考虑了各向异性和零场分裂的扩展海森堡哈密顿量，对具有 S = 3/2 (Cu(II)) 和 S = 5/2 (Ni(II)) 基态的氰化物桥接、铁磁耦合顺式和反式 Fe[ML]2 化合物 (M = Ni(II)、Cu(II)) 的磁性数据进行了分析，并且根据以下公式对具有可用结构的 Cu(II) 系统的数据进行了彻底分析：轨道相关的海森堡哈密顿量，其中同时考虑自旋轨道耦合和低对称性配体场。结果表明，这里报道的所有自旋簇中单分子磁性行为的缺失是由于[Fe(CN)6](3-)中心的大角度畸变以及伴随的Fe(III)((2)T2g)基态轨道角动量的猝灭。
The reaction of the hexacyanometalates K3[M(1)(CN)6] (M(1) = Cr(III), Fe(III), Co(III)) with the bispidine complexes [M(2)(L(1))(X)](n+) and [M(2)(L(2))(X)](n+) (M(2) = Mn(II), Ni(II), Cu(II); L(1) = 3-methyl-9-oxo-2,4-di-(2-pyridyl)-7-(2-pyridylmethyl)-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarboxylic acid dimethyl ester; L(2) = 3-methyl-9-oxo-7-(2-pyridylmethyl)-2,4-di-(2-quinolyl)-3,7-diazabicyclo[3.3.1]nonane-1,5-dicarboxylic acid dimethyl ester; X = anion or solvent) in water-methanol mixtures affords trinuclear complexes with cis- or trans-arrangement of the bispidine-capped divalent metal centers around the hexacyanometalate. X-ray structural analyses of five members of this family of complexes (cis-Fe[CuL(2)]2, trans-Fe[CuL(1)]2, cis-Co[CuL(2)]2, trans-Cr[MnL(1)]2, trans-Fe[MnL(1)]2) and the magnetic data of the entire series are reported. The magnetic data of the cyanide bridged, ferromagnetically coupled cis- and trans-Fe[ML]2 compounds (M = Ni(II), Cu(II)) with S = 3/2 (Cu(II)) and S = 5/2 (Ni(II)) ground states are analyzed with an extended Heisenberg Hamiltonian which accounts for anisotropy and zero-field splitting, and the data of the Cu(II) systems, for which structures are available, are thoroughly analyzed in terms of an orbital-dependent Heisenberg Hamiltonian, in which both spin-orbit coupling and low-symmetry ligand fields are taken into account. It is shown that the absence of single-molecule magnetic behavior in all spin clusters reported here is due to a large angular distortion of the [Fe(CN)6](3-) center and the concomitant quenching of orbital angular momentum of the Fe(III) ((2)T2g) ground state.