Syntheses of Highly Functionalized Metal Complexes as Models of Metal Proteins

1,2-二[2-（二（2-吡啶基甲基）氨基甲基）-6-吡啶基]乙烷（6-HPA）是一种新的二核配体，其中两个三（2-吡啶基甲基）胺（TPA）单元在6-py位置连接到- ch_2ch_2 -链上。6-HPA形成二铁（III）配合物[Fe_2(6-HPA)(O)(OH_2)_2](ClO_4)_4(1)，作为sMMO的功能模型。通过x射线分析确定了1的晶体结构。在双铁核稳定的情况下，1与H_2O_2催化烯烃的主要环氧化反应，收率高，周转率大；反式β-甲基苯乙烯生成的反式环氧化物收率为91%，周转率超过100。低电离势烯烃的高环氧化物产率和顺式β-甲基苯乙烯的反式环氧化物产率表明烯烃发生了单电子氧化。给出的自由基阳离子部分由顺式重排为反式。在-40℃条件下，在MeCN中加入2 eq H_2O_2至1，生成绿色物种4。490 nm (1130 M^<-1> cm^<-1>), 670（1060）和882 （sh, 370）的电子吸收数据表明，CSI质谱的主峰位于M /z 865，当H_2^<18>O_2时向M /z 869偏移，表明4是μ-氧-μ-过氧二铁（III）。以反式β-甲基苯乙烯为底物，在H2^<18>O_2、μ-^<18>O-1、H_2^<18>O和^<18>O_2等不同条件下进行了^<18>O标记实验，以了解O_2的活化机理。在氩气作用下，H_2^<18>O_2/1 （10/1, mol/mol）的环氧化物中有94%的氧被掺入，而在氩气作用下，H_2^<16>O_2/μ-^<18>O-1（1/1）或（3/1）的环氧化物中有31%或17%的氧被掺入。结果表明，4中μ-O和μ-O_2的O原子等量掺入。通过O-O键的均裂，其中三个o-原子相互争夺，4可以转化为二氧o-μ-氧二铁（IV）。

1,2-Bis[2-(bis(2-pyridylmethyl)aminomethyl)-6-pyridyl]ethane (6-HPA) was prepared as a new dinucleating ligand, where two tris(2-pyridylmethyl)amine (TPA) units are attached to a -CH_2CH_2- tether at the 6-py position. 6-HPA forms the diiron(III) complex [Fe_2(6-HPA)(O)(OH_2)_2](ClO_4)_4 (1), which acts as functional models of sMMO. Crystal structure of 1 was determined by X-ray analysis. Given the stable diiron core, 1 catalyzes the predominant epoxidation of the alkene with H_2O_2, where both a high yield and large turnover number were attained; trans-β-methylstyrene gave the trans-epoxide in 91% yield and the turnover number exceeded one hundred. A high epoxide yield for the alkene with low ionization potential and trans-epoxide production from cis-β-methylstyrene indicated that a one-electron oxidation of the alkene had occurred. The radical cation given was partly rearranged from cis to trans. The addition of 2 eq of H_2O_2 to 1 at -40℃ in MeCN generated a green species 4. The electronic absorption data, 490 nm (1130 M^<-1> cm^<-1>), 670 (1060), and 882 (sh, 370), with the main peak of the CSI MS at m/z 865, and a shift to m/z 869 with H_2^<18>O_2 shows that 4 is a μ-oxo-μ-peroxodiiron(III). ^<18>O-labeling experiments using trans-β-methylstyrene as a substrate were carried out under various conditions using H2^<18>O_2, μ-^<18>O-1, H_2^<18>O, and ^<18>O_2 to gain some insights into the O_2-activation mechanism. ^<18>O was incorporated into 94% of the epoxide with H_2^<18>O_2/1 (10/1, mol/mol) under Ar and into 31 or 17% of the epoxide with H_2^<16>O_2/μ-^<18>O-1 (1/1) or (3/1) under Ar. The data clearly showed that O-atoms of μ-O and μ-O_2 in 4 were incorporated equivalently into the epoxide. 4 may be converted to a dioxo-μ-oxodiiron(IV) via homolytic scission of the O-O bond, where three O-atoms scramble one another.