A new family of spin crossover complexes with a tripod ligand containing three imidazoles: synthesis, characterization, and magnetic properties of [FeIIH3LMe](NO3)2.1.5H2O, [FeIIILMe].3.5H2O, [FeIIH3LMe][FeIILMe]NO3, and [FeIIH3LMe][FeIIILMe](NO3)2 (H3LMe) = Tris[2-(((2-methylimidazol-4-yl)methylide
A new family of spin crossover complexes with a tripod ligand containing three imidazoles: synthesis, characterization, and magnetic properties of [FeIIH3LMe](NO3)2.1.5H2O, [FeIIILMe].3.5H2O, [FeIIH3LMe][FeIILMe]NO3, and [FeIIH3LMe][FeIIILMe](NO3)2 (H3LMe) = Tris[2-(((2-methylimidazol-4-yl)methylide
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DOI：
10.1021/ic034495f
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发表时间：
2003-11
影响因子：
4.6
通讯作者：
Yuichi Ikuta;Makoto Ooidemizu;Yuichi Yamahata;M. Yamada;S. Osa;N. Matsumoto;S. Iijima;Y. Sunatsuki;M. Kojima;F. Dahan;J. Tuchagues
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作者：
Yuichi Ikuta;Makoto Ooidemizu;Yuichi Yamahata;M. Yamada;S. Osa;N. Matsumoto;S. Iijima;Y. Sunatsuki;M. Kojima;F. Dahan;J. Tuchagues
合成并表征了一系列新的自旋交叉配合物：[Fe(II)H₃L(Me)](NO₃)₂·1.5H₂O（1）、[Fe(III)L(Me)]·3.5H₂O（2）、[Fe(II)H₃L(Me)][Fe(II)L(Me)]NO₃（3）和[Fe(II)H₃L(Me)][Fe(III)L(Me)](NO₃)₂（4），其中H₃L(Me)表示一种含三个咪唑基团的六齿N₆三脚架配体，即三[2 - (((2 - 甲基咪唑 - 4 - 基)亚甲基)氨基)乙基]胺。研究发现，具有这种三脚架配体的铁配合物的自旋和氧化态受咪唑基团的去质子化程度以及2 - 甲基咪唑取代基的调控。磁化率和穆斯堡尔研究表明，1是高自旋（HS）-Fe(II)配合物，2在高自旋和低自旋（LS）-Fe(III)之间呈现自旋平衡，3呈现两步自旋转变，其中去质子化配体的组分[Fe(II)L(Me)]⁻在较高温度范围参与自旋转变过程，而中性配体的组分[Fe(II)H₃L(Me)]²⁺在较低温度范围参与自旋转变过程，4呈现Fe(II)和Fe(III)位点的自旋转变。3的晶体结构由同手性的二维褶皱片层组成，其中帽状三脚架状组分[Fe(II)H₃L(Me)]²⁺和[Fe(II)L(Me)]⁻以上下交替的方式排列，并通过咪唑 - 咪唑酸氢键连接。此外，相邻的二维同手性片层在晶格中堆叠，形成外消旋聚集体，这通过对映圆二色性光谱得到证实。化合物3和4在分别用绿光和红光照射时显示出光诱导激发自旋态捕获（LIESST）效应和反LIESST效应。
A new family of spin crossover complexes, [Fe(II)H(3)L(Me)](NO(3))(2).1.5H(2)O (1), [Fe(III)L(Me)].3.5H(2)O (2), [Fe(II)H(3)L(Me)][Fe(II)L(Me)]NO(3) (3), and [Fe(II)H(3)L(Me)][Fe(III)L(Me)](NO(3))(2) (4), has been synthesized and characterized, where H(3)L(Me) denotes a hexadentate N(6) tripod ligand containing three imidazole groups, tris[2-(((2-methylimidazol-4-yl)methylidene)amino)ethyl]amine. It was found that the spin and oxidation states of the iron complexes with this tripod ligand are tuned by the degree of deprotonation of the imidazole groups and by the 2-methyl imidazole substituent. Magnetic susceptibility and Mössbauer studies revealed that 1 is an HS-Fe(II) complex, 2 exhibits a spin equilibrium between HS and LS-Fe(III), 3 exhibits a two-step spin transition, where the component [Fe(II)L(Me)](-) with the deprotonated ligand participates in the spin transition process in the higher temperature range and the component [Fe(II)H(3)L(Me)](2+) with the neutral ligand participates in the spin transition process in the lower temperature range, and 4 exhibits spin transition of both the Fe(II) and Fe(III) sites. The crystal structure of 3 consists of homochiral extended 2D puckered sheets, in which the capped tripodlike components [Fe(II)H(3)L(Me)](2+) and [Fe(II)L(Me)](-) are alternately arrayed in an up-and-down mode and are linked by the imidazole-imidazolate hydrogen bonds. Furthermore, the adjacent 2D homochiral sheets are stacked in the crystal lattice yielding a conglomerate as confirmed by the enantiomeric circular dichorism spectra. Compounds 3 and 4 showed the LIESST (light induced excited spin state trapping) and reverse-LIESST effects upon irradiation with green and red light, respectively.