亚铁烷基咪唑自旋交叉配合物的合成及其金属有机凝胶性能 |
Synthesis and Gelation Ability of Spin-Crossover Iron(Ⅱ) Alkyl Imidazole Complexes |
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摘要: 通过1-庚烷基-1H-咪唑-2-甲醛(L1)、1-十四烷基-1H-咪唑-2-甲醛(L2)、1-十六烷基-1H-咪唑-2-甲醛(L3)、1-十八烷基-1H-咪唑-2-甲醛(L4)、1-二十烷基-1H-咪唑-2-甲醛(L5)分别和四氟硼酸亚铁与1-苯乙胺反应一步法合成了配合物1~5。利用红外光谱(IR)、元素分析(EA)手段对1~5进行表征。配合物1的X射线单晶衍射结构研究表明,每个结构基元中包含1个[Fe(L1)3]2+阳离子和2个四氟硼酸根阴离子。铁(Ⅱ)金属中心与3个配体上的6个N原子配位,形成面式八面体单核化合物。Fe(Ⅱ)-N键长表明配合物1中的Fe(Ⅱ)在173 K时处于低自旋状态。在[Fe(L1)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;[Fe(L1)3]2+进一步通过烷基链与芳香环之间的C-H…π相互作用形成超分子网络结构。磁性测试表明,配合物1表现出不完全的自旋交叉性能,转换温度为341 K;2为髙自旋顺磁性化合物,3~5则表现出不完全的自旋交叉行为。以具有较长烷基链的配合物2~5作为凝胶因子,环己烷作为溶剂可形成对应的金属有机凝胶MOG2~MOG5。扫描电子显微镜(SEM)图片显示MOG2~MOG5凝胶都具有三维网络状孔隙结构。MOG2~MOG5表现出可逆的凝胶-溶胶转变,在热和机械力的作用下,MOG2~MOG5金属有机凝胶迅速转变为溶胶状态,且静置后能够恢复至凝胶状态,表现出良好的刺激响应性和自修复能力。 |
关键词: Fe(Ⅱ)配合物 自旋交叉 金属有机凝胶 刺激响应性 |
基金项目: 国家自然科学基金(No.21771089)和中央高校基本科研业务经费(No.JUSRP21936,JUSRP51725B)资助项目。 |
Abstract: Complexes 1~5 were synthesized by one-step reaction of 1-heptyl-1H-imidazole-2-carboxaldehyde(L1), 1-tetradecyl-1H-imidazole-2-carbaldehyde(L2), 1-hexadecyl-1H-imidazole-2-carbaldehyde(L3), 1-octadecyl-1H-imidazole-2-carboxaldehyde(L4), 1-eicosyl-1H-imidazole-2-carboxaldehyde(L5) with ferrous tetrafluoroborate and 1-phenylethylamine, respectively. The five complexes have been determined by IR spectra and elemental analysis. X-ray crystallography reveals that each unit in 1 contains one[Fe(L1)3]2+ cation and two BF4- anions. The iron(Ⅱ) center coordinates with six N donor atoms from three ligands to form a octahedral mononuclear compound with fac-configuration. The Fe(Ⅱ)-N bond distances indicate that the Fe(Ⅱ) sites of 1 are in low-spin state. As for[Fe(L1)3]2+, intramolecular π-π interactions are present between phenyl group and imidazole ring of an adjacent ligand, and then a supramolecular architectures are further formed by C-H…π interactions between alkyl chain and aromatic ring. Magnetic measurements reveal that 1 displays incomplete spin-crossover behaviour at 341 K, and 2 is a high-spin paramagnetic compound, while 3~5 show incomplete spin-crossover behaviour. The corresponding metallogels MOG2~MOG5 were formed by using complexes 2~5 with longer alkyl chains as gelator and cyclohexane as solvent. Scanning electron microscopy(SEM) images showed that the MOG2~MOG5 had 3D network pore structure. Reversible gel-sol transitions were found in MOG2~MOG5. Under the influence of heat and mechanical force, MOG2~MOG5 were rapidly converted to sol, which can be restored to gel after being stationary, showing good stimulation-response and self-healing ability. |
Keywords: Fe(Ⅱ) complexes spin-crossover metallogels stimulus responsiveness |
投稿时间:2019-06-05 修订日期:2019-08-01 |
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王娅琴,张海霞,张舒恒,何威,葛芳圆,陈雨欣,顾志国.亚铁烷基咪唑自旋交叉配合物的合成及其金属有机凝胶性能[J].无机化学学报,2019,35(12):2260-2268. |
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Support information: 相关附件: file190265_190265_Supporting_Information.doc |
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