| 手性自旋转换铁(Ⅱ)席夫碱配合物的合成、结构及其磁性研究 | |
| Syntheses, Structures and Magnetic Properties of Homochiral Spin-Crossover Iron(Ⅱ) Schiff-Base Complexes | |
| 摘要: 通过高氯酸亚铁, 4-(咪唑-2-甲醛)丁腈和光学纯苯乙胺衍生物的自组装成功合成了2个纯手性单核自旋转换铁(Ⅱ)化合物fac-Λ-[Fe(R-L1)3](ClO4)2(1), fac-Λ-[Fe(R-L2)3](ClO4)2(2)。利用X-射线单晶衍射、元素分析(EA)、红外光谱(IR)、核磁共振氢谱(1H NMR)、紫外光谱(UV)、圆二光谱(CD)等手段对配合物结构进行了表征。X-射线单晶衍射表明在化合物1和2中, 铁(Ⅱ)金属中心与3个不对称双齿手性席夫碱配体中的6个氮原子配位形成八面体配位环境。每个结构基元中包含1个[Fe(L)3]2+阳离子和2个高氯酸根阴离子。由于铁(Ⅱ)中心周围手性配体的螺旋协调配位使[Fe(L)3]2+形成单一手性Λ构型。Fe(Ⅱ)-N键长表明配合物1和2中的铁(Ⅱ)在低自旋状态。在[Fe(L)3]2+中, 相邻配体中的苯环和咪唑环形成分子内π-π相互作用。配合物1和2通过分子间C-H…π相互作用形成三维超分子结构。CD光谱证实配合物1和2在溶液中的光学活性。磁性测试表明配合物1和2分别在232和250 K发生自旋转换。由于配合物1和2具有相同的手性空间群和类似的堆积方式和分子间相互作用, 导致1和2表现出不同自旋转换温度的原因主要是取代基效应。 | |
| 关键词: 纯手性 自旋转换 铁(Ⅱ)配合物 席夫碱 | |
| 基金项目: 国家自然科学基金(No.21101078, 21276105)、新世纪优秀人才计划(No.NCET-11-0657), 江苏省自然科学基金(No.BK2011143)资助。 | |
| Abstract: Two homochiral mononuclear spin-crossover iron(Ⅱ) complexes, namely, fac-Λ-[Fe(R-L1)3](ClO4)2 (1), fac-Λ-[Fe(R-L2)3](ClO4)2 (2) have been successfully synthesized by subcomponent self-assembly of Fe(ClO4)2, 4-(imidazole-2-carboxaldehyde)butyronitrile and optical phenylethylamine derivatives. The two complexes have been determined by single-crystal X-ray diffraction analysis, elemental analysis, IR spectra, 1H NMR spectra, UV spectra and CD spectra. X-ray crystallography revealed that the iron(Ⅱ) center in 1 and 2 assumed an octahedral coordination environment with six N donor atoms from three unsymmetrical bidentate chiral schiff-base ligands. Each unit contained one [Fe(L)3]2+ cation and two ClO4- anions. [Fe(L)3]2 components were chiral with Λ configuration due to the screw coordination arrangement of the chiral ligand around Fe(Ⅱ) centers. The Fe(Ⅱ)-N bond distances indicated that the Fe(Ⅱ) sites of 1 and 2 were in low-spin state. As for [Fe(L)3]2+, intramolecular π-π interactions were present between phenyl group and imidazole ring of an adjacent ligand. In 1 and 2, 3D supramolecular architectures were formed through intermolecular C-H…π interactions. Circular dichromism spectra confirmed the presence of non-racemic chiral metal centers in solution for complexes 1 and 2. Magnetic measurements revealed that 1 and 2 displayed obviously spin-crossover behaviour at 232 and 250 K, respectively. Complexes 1 and 2 crystallized in the same chiral space group with similar packing modes and intermolecular interactions, therefore their different SCO bahaviors mainly resulted from substitution effect. | |
| Keywords: homochiral spin-crossover iron(Ⅱ) complexes schiff-base | |
| 投稿时间：2014-10-17 修订日期：2014-11-10 | |
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| 任冬红,刘志明,孙晓利,顾玲,邱丹,顾志国,李在均.手性自旋转换铁(Ⅱ)席夫碱配合物的合成、结构及其磁性研究[J].无机化学学报,2015,31(3):536-542. | |
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| Support information: 相关附件： file140726_Supporting Information.doc | |
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