Spectroscopic properties of p/p and o/o type iron(III)‐metal‐free porphyrin dimers and their catalysis as Cytochrome P450 model
Spectroscopic properties of p/p and o/o type iron(III)‐metal‐free porphyrin dimers and their catalysis as Cytochrome P450 model
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DOI：
10.1002/jpp.337
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发表时间：
2001-05
影响因子：
1.5
通讯作者：
Q. Ren;Jin-wang Huang;Zhi-ang Zhu;L. Ji;Y. Chen
中科院分区：
文献类型：
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作者：
Q. Ren;Jin-wang Huang;Zhi-ang Zhu;L. Ji;Y. Chen
合成并表征了两个系列的p/p和o/o型无铁金属卟啉二聚体。二聚体由铁卟啉和游离碱卟啉组成，在两个苯环的帕拉和邻位上与烷氧基链-O（CH 2）nO-（n = 2-10）共价连接。通过1H NMR研究了二聚体的铁顺磁效应和环电流效应;通过IR研究了对二聚体构象敏感的振动模式;通过XPS和EPR研究了铁离子的电子密度和自旋态。在温和条件下研究了p/p型和o/o型二聚体对环己烷羟基化反应的催化活性。作为Cyto的化学模拟模型。P450，这些卟啉表现出比相应单体FeTPPCl更高的催化活性。随着烷氧基碳数的增加，p/p二聚体的催化活性顺序为C2-C8 > C10，o/o二聚体的催化活性顺序为C2 > C4 > C6 > C8 > C10。二聚体的催化效果强烈依赖于它们特殊的构象平衡，这种构象平衡影响着两个卟啉环之间的空间位阻和电子转移。
Two series of p/p and o/o type iron(III)-metal-free porphyrin dimers were synthesized and characterized. The dimers consist of a ferric porphyrin and a free-base porphyrin, covalently linked with an alkoxy chain -O(CH2)nO-(n = 2–10) at the para and ortho position of two phenyl rings. The ferric paramagnetic effect and ring current effect on these dimers were discussed by 1H NMR study; vibration modes sensitive to the conformations of the dimers were investigated from IR spectra; the electron density and spin state of ferric ion were examined using XPS and EPR spectroscopy. The catalytic activities of p/p and o/o type dimers on the hydroxylation of cyclohexane were studied under mild conditions. As a chemical mimic model of Cyto. P450, these porphyrins exhibit higher catalytic activities than the corresponding monomer FeTPPCl. With increase of the carbon numbers of alkoxy chain, the catalytic activity order of p/p dimers is C2 C8 > C10, the corresponding order of o/o dimers is C2 > C4 > C6 > C8 > C10. Catalytic results of dimers are shown to strongly depend on their special conformation equilibrium, which affect the steric hindrance and electron transfer between two porphyrin rings.