Two MOFs, [H₂N(CH₃)₂][Zn₃(TATB)₂(HCOO)]·HN(CH₃)₂·DMF·6H₂O (1) and Zn-HKUST-1 (2), were investigated as potential hosts to encapsulate Fe(III) heme (Fe(III) protoporphyrin IX = Fe(III)PPIX). Methyl orange (MO) adsorption was used as an initial model for substrate uptake. MOF 1 showed good adsorption of MO (10.3 ± 0.8 mg g^–1) which could undergo in situ protonation upon exposure to aqueous HCl vapor. By contrast, MO uptake by 2 was much lower (2 ± 1 mg g^–1), and PXRD indicated that structural instability on exposure to water was the likely cause. Two methods for Fe(III)PPIX-1 preparation were investigated: soaking and encapsulation. Encapsulation was verified by SEM-EDS and showed comparable concentrations of Fe(III)PPIX on exposed interior surfaces and on the original surface of fractured crystals. SEM-EDS results were consistent with ICP-OES data on bulk material (1.2 ± 0.1 mass % Fe). PXRD data showed that the framework in 1 was unchanged after encapsulation of Fe(III)PPIX. MO adsorption (5.8 ± 1.2 mg g^–1) by Fe(III)PPIX-1 confirmed there is space for substrate diffusion into the framework, while the UV–vis spectrum of solubilized crystals confirmed that Fe(III)PPIX retained its integrity. A solid-state UV–vis spectrum of Fe(III)PPIX-1 indicated that Fe(III)PPIX was not in a μ-oxo dimeric form. Although single-crystal XRD data did not allow for full refinement of the encapsulated Fe(III)PPIX molecule owing to disorder of the metalloporphyrin, the Fe atom and pyrrole N atoms were located, enabling rigid-body modeling of the porphine core. Reaction of 2,2′-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) with H₂O₂, catalyzed by Fe(III)PPIX-1 and -2, showed that Fe(III)PPIX-1 is significantly more efficient than Fe(III)PPIX-2 and is superior to solid Fe(III)PPIX-Cl. Fe(III)PPIX-1 was used to catalyze the oxidation of hydroquinone, thymol, benzyl alcohol, and phenyl ethanol by tert-butyl-hydroperoxide with t_1/2 values that increase with increasing substrate molecular volume.

中文翻译：

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Fe（III）原卟啉IX封装在锌金属-有机框架中显示出显着增强的过氧化活性

两个MOF，[H ₂ N（CH ₃）₂ ] [Zn ₃（TATB）₂（HCOO）]·HN（CH ₃）₂ ·DMF·6H ₂ O（1）和Zn-HKUST-1（2），被调查为潜在的宿主来封装Fe（III）血红素（Fe（III）原卟啉IX = Fe（III）PPIX）。甲基橙（MO）吸附用作底物吸收的初始模型。MOF 1显示出对MO的良好吸附（10.3±0.8 mg g ^–1），当暴露于HCl水溶液中时，MO可以原位质子化。与此相反，MO摄取2低得多（2±1毫克克^-1），PXRD表示可能是由于暴露于水引起的结构不稳定性。研究了两种制备Fe（III）PPIX- 1的方法：浸泡和包封。通过SEM-EDS验证了包封，并且在暴露的内表面和破裂的晶体的原始表面上显示出相当浓度的Fe（III）PPIX。SEM-EDS结果与散装材料（1.2±0.1质量％Fe）上的ICP-OES数据一致。PXRD数据表明，Fe（III）PPIX包封后1中的骨架没有变化。Fe（III）PPIX- 1的MO吸附（5.8±1.2 mg g ^–1）证实有底物扩散到框架中的空间，而可溶晶体的UV-vis光谱证实Fe（III）PPIX保持其完整性。Fe（III）PPIX- 1的固态紫外-可见光谱表明，Fe（III）PPIX不是μ-氧代二聚体形式。尽管由于金属卟啉的无序性，单晶XRD数据无法完全精炼所包封的Fe（III）PPIX分子，但仍定位了Fe原子和吡咯N原子，从而可以对卟啉核心进行刚性建模。Fe（III）PPIX- 1和-2催化2,2'-叠氮基双（3-乙基苯并噻唑啉）-6-磺酸（ABTS）与H ₂ O ₂反应，表明Fe（III）PPIX- 1个与Fe（III）PPIX- 2相比效率更高，并且优于固态Fe（III）PPIX-Cl。Fe（III）PPIX- 1用于催化叔丁基氢过氧化氢对苯二酚，百里酚，苯甲醇和苯乙醇的氧化，t _1/2值随底物分子体积的增加而增加。