| 亚铁金属有机层的合成、结构及其超快仿生催化性能 |
| An Iron(Ⅱ) Metal-Organic Layer: Synthesis, Structure and Ultrafast Biomimetic Catalytic Performance |
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| 摘要: 六水合四氟硼酸亚铁、三水合四氰基铂酸钾和4-甲基吡啶-N-氧化物在水和乙醇中自组装形成了一种新的二维金属有机框架(Fe-MOF)。单晶结构分析表明，Fe-MOF 结晶于单斜空间群 P21/c。在 Fe-MOF 中，每个[Pt(CN)4]2-通过氰基桥联 4 个 Fe 原子，而每个Fe原子与4个[Pt(CN)4]2-的N相连形成二维(4,4)网格结构。二维层之间通过范德华力沿c轴形成AB堆积，层间距约为0.6 nm。亚铁中心存在2种[FeN4O2]八面体配位环境，一种亚铁离子的轴向与2个水分子配位，而另一种亚铁离子的轴向与1个水分子和1个4-甲基吡啶-N-氧化物配位。Fe-MOF可通过超声剥离形成亚铁金属有机层(Fe-MOL)。红外光谱(FT-IR)和X射线粉末衍射(PXRD)分析表明，Fe-MOL 保持二维晶态结构。扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征显示 Fe-MOL为纳米层状结构。原子力显微镜(AFM)分析结果表明Fe-MOL为5 nm左右超薄层状结构。得益于亚铁中心的配位环境与天然血红素相似，Fe-MOL在2，2'-联氮-双(3-乙基苯并噻唑啉-6-磺酸)二铵盐(ABTS)的催化氧化反应中展现出超快的催化速率和超高的催化效率，反应溶液在16 s内由无色变为深绿色，表观二级速率常数(kcat/Km；kcat为催化常数，Km为米氏常数)高达4.70×106mmol-1·L·s-1。Fe-MOL具有良好的催化循环稳定性，5次循环后仍然具有90%的催化活性。Fe-MOL优异的催化效率超过了大部分已报道的MOF类仿生催化剂。 |
| 关键词: 二维金属有机框架 超声剥离 金属有机层 仿生催化 催化速率 |
| 基金项目: 国家自然科学基金(No.22075108，21771089，21905116)和江苏省自然科学基金资助项目(No.BK20190614)资助 |
| Abstract: A new two-dimensional metal-organic framework (Fe-MOF) was self-assembled by ferrous tetrafluoroborate hexahydrate, potassium tetracyanoplatinate trihydrate, and 4-picoline-N-oxide in water and ethanol. Singlecrystal X-ray crystallography reveals that Fe-MOF crystallized in the monoclinic space group P21/c. [Pt(CN)4]2- is bridged by four Fe atoms through the cyano group, while Fe atom is connected with four N atoms from [Pt(CN)4]2-, forming Fe-MOF with (4,4)-grid structure. Fe-MOF is stacked by a two-dimensional layer in an AB mode along the caxis by virtue of van der Waals forces, and the layer distance is 0.6 nm. The Fe(Ⅱ) centers have two [FeN4O2] octahedral coordination environments: one of them is connected axially with two water molecules, while the other is connected axially with a water molecule and a 4-picoline-N-oxide. Metal-organic layer (Fe-MOL) was prepared by ultrasonically exfoliating Fe-MOF. Fe-MOL maintained the two-dimensional crystalline structure as evidenced by infrared spectroscopy (FT-IR) and X-ray powder diffraction (PXRD). Scanning electron microscope (SEM) and transmission electron microscope (TEM) characterizations showed that Fe-MOL had a nanolayered structure. Fe-MOL was proved to be an ultra-thin layered structure of about 5 nm by atomic force microscopy (AFM). Fe-MOL exhibited ultrafast catalytic speed and ultrahigh catalytic efficiency in the catalytic oxidation reaction of 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) due to the coordination environment of the Fe(Ⅱ) center possessing a similar natural heme structure. The color of the solution changed from colorless to dark green in just 16 s, and the apparent second-order rate constant (kcat/Km; kcat is catalytic constant, Km is Michaelis constant) was as high as 4.70×106 mmol-1·L·s-1. Fe-MOL exhibited good cycle stability and it still had 90% catalytic activity after five catalytic cycles. The excellent catalytic efficiency of Fe-MOL exceeded most of the reported MOF biomimetic catalysts. |
| Keywords: 2D metal-organic framework ultrasonic exfoliation metal-organic layer biomimetic catalysis catalysis rate |
| 投稿时间：2021-11-14 修订日期：2022-01-13 |
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| 陈宇轩,龚裕,张文达,晏晓东,顾志国.亚铁金属有机层的合成、结构及其超快仿生催化性能[J].无机化学学报,2022,38(3):519-527. |
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| Support information: 相关附件： file支持信息 fileFe-MOF-checkcif |
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