Supramolecular spin-crossover iron complexes based on imidazole-imidazolate hydrogen bonds.
Supramolecular spin-crossover iron complexes based on imidazole-imidazolate hydrogen bonds.
复制标题
DOI：
10.1021/ic0498384
复制
发表时间：
2004-07
影响因子：
4.6
通讯作者：
Y. Sunatsuki;Hiromi Ohta;M. Kojima;Yuichi Ikuta;Y. Goto;N. Matsumoto;S. Iijima;H. Akashi;
中科院分区：
文献类型：
--
作者：
Y. Sunatsuki;Hiromi Ohta;M. Kojima;Yuichi Ikuta;Y. Goto;N. Matsumoto;S. Iijima;H. Akashi;
合成了[Fe（II）（H（3）L）]（BF（4））（2）. 3 H（2）O（1）配合物，其中H（3）L（三[[2-[（咪唑-4-基）亚甲基]氨基]乙基]胺）是由三（2-氨基乙基）胺和4-甲酰咪唑（fim）以1：3的摩尔比缩合得到的三脚架配体。从1开始，一系列配合物，[Fe（II）]（H（1.5）L）]（BF（4））（0.5）（2）（=[Fe（II）（H（3）L）][Fe（II）（L）]BF（4）），[Fe（H（1.5）L）]BF（4）（3）（=[Fe（II）（H（3）L）][Fe（III）（L）]（BF（4））（2））、[Fe（III）（H（3）L）]（BF（4））（3）fim.H（2）O（4）和[Fe（III）（L）].2.5H（2）O（5）。测定了各配合物的单晶X-射线结构。Fe（II）化合物2和混合价Fe（II）-Fe（III）化合物3在形式上涉及半去质子化配体H（1.5）L。化合物3的结构是由[Fe（II）（H（3）L）]（2+）和[Fe（III）（L）]（0）（3）之间的分子间氢键形成的纯手性二维组装片。除了5个外，所有的都表现出低自旋（LS）和高自旋（HS）状态之间的自旋交叉。这是一种罕见的情况下，两个Fe（II）和Fe（III）配合物含有相同的配体表现出自旋交叉行为。磁化率和穆斯堡尔研究表明，3有三种可接近的电子状态：LS Fe（II）-LS Fe（III），HS Fe（II）-LS Fe（III）和HS Fe（II）-HS Fe（III）。化合物1-3在用绿色光照射时在Fe（II）位点显示光诱导的激发自旋态捕获效应。研究了化合物1、4和5的溶液磁性、电子光谱和电化学性质。
The [Fe(II)(H(3)L)](BF(4))(2).3H(2)O (1) complex was synthesized, where H(3)L (tris[[2-[(imidazole-4-yl)methylidene]amino]ethyl]amine) is a tripodal ligand obtained by condensation of tris(2-aminoethyl)amine and 4-formylimidazole (fim) in a 1:3 molar ratio. Starting from 1, a series of complexes, [Fe(II)(H(1.5)L)](BF(4))(0.5) (2) (=[Fe(II)(H(3)L)][Fe(II)(L)]BF(4)), [Fe(H(1.5)L)]BF(4) (3) (=[Fe(II)(H(3)L)][Fe(III)(L)](BF(4))(2)), [Fe(III)(H(3)L)](BF(4))(3).fim.H(2)O (4), and [Fe(III)(L)].2.5H(2)O (5), has been synthesized and characterized. The single-crystal X-ray structure of each complex has been determined. The Fe(II) compound, 2, and a mixed valence Fe(II)-Fe(III) compound, 3, involve formally hemi-deprotonated ligands, H(1.5)L. The structure of 3 consists of a homochiral two-dimensional assembled sheet, arising from the intermolecular hydrogen bonds between [Fe(II)(H(3)L)](2+) and [Fe(III)(L)](0) (3). All but 5 exhibit spin crossover between low-spin (LS) and high-spin (HS) states. This is a rare case where both Fe(II) and Fe(III) complexes containing the same ligand exhibit spin-crossover behavior. Magnetic susceptibility and Mössbauer studies showed that 3 has three accessible electronic states: LS Fe(II)-LS Fe(III), HS Fe(II)-LS Fe(III), and HS Fe(II)-HS Fe(III). Compounds 1-3 show the light-induced excited spin-state trapping effect at the Fe(II) sites upon irradiation with green light. The solution magnetic properties, electronic spectra, and electrochemical properties of 1, 4, and 5 were also studied.