Modeling the Mononuclear, Dinuclear, and Trinuclear Copper(I) Reaction Centers of Copper Proteins Using Pyridylalkylamine Ligands Connected to 1,3,5-Triethylbenzene Spacer
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- 作者：Hiromi Ohi ; Yoshimitsu Tachi ; Shinobu Itoh
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：December 25, 2006
- 年：2006
- 卷：45
- 期：26
- 页码：10825 - 10835
- 全文大小：428K
- 年卷期：v.45,no.26(December 25, 2006)
- ISSN：1520-510X
文摘
The structure and O2-reactivity of copper(I) complexes supported by novel ligands, Pye2 (1,3,5-triethyl-2,4-bis((N-benzyl-N-(2-(pyridin-2-yl)ethyl)-)aminomethyl)benzene), Pye3 (1,3,5-triethyl-2,4,6-tris((N-benzyl-N-(2-(pyridin-2-yl)ethyl))aminomethyl)benzene), MePym2 (1,3,5-triethyl-2,4-bis((N-benzyl-N-(6-methylpyridin-2-ylmethyl))aminomethyl)benzene), and MePym3 (1,3,5-triethyl-2,4,6-tris((N-benzyl-N-(6-methylpyridin-2-ylmethyl))aminomethyl)benzene) havebeen examined. The ligands are designed to construct mono-, di-, and trinuclear copper(I) complexes by connectingtwo or three pyridylalkylamine metal-binding sites to a 1,3,5-triethylbenzene spacer. Thus, the reaction of the ligandswith [CuI(CH3CN)4]X (X = PF6, CF3SO3) or CuICl gave the expected mononuclear copper(I) complexes [CuI(Pye2)(CF3SO3)] (1) and [CuI(Pye3)](CF3SO3) (2), dinuclear copper(I) complex [CuI2(MePym2)(Cl)]CuICl2 (3), and trinuclearcopper(I) complex [CuI3(MePym3)(CH3CN)3](CF3SO3)3 (4), the structures of which were determined by X-raycrystallographic analysis. The mononuclear copper(I) complexes, 1 and 2, exhibit a distorted three-coordinate T-shapestructure and a trigonal planar structure, respectively, which are very close to the coordination geometry of theCuA site of PHM (peptidylglycine 
-hydroxylating monooxygenase) and the CuB site of CcO (cytochrome c oxidase).Notably, 1 and 2 showed a significantly high oxidation potential (990 mV vs SCE), thus showing virtually no reactivitytoward O2. On the other hand, the metal centers of the dinuclear and trinuclear copper(I) complexes, 3 and 4,exhibit a distorted trigonal planar geometry and a trigonal pyramidal geometry, respectively. In contrast to themononuclear copper(I) complexes, these dinuclear and trinuclear copper(I) complexes reacted with O2 to inducean aromatic ligand hydroxylation reaction involving an NIH-shift of one of the ethyl substituents on the benzenespacer. The NIH-shift of the alkyl substituent on the aromatic ring is strong evidence of the electrophilic aromaticsubstitution mechanism, although the active oxygen intermediate could not be directly detected during the courseof the reaction. The biological relevance of the copper(I) complexes is also discussed on the basis of structure andO2-reactivity.
-hydroxylating monooxygenase) and the CuB site of CcO (cytochrome c oxidase).Notably, 1 and 2 showed a significantly high oxidation potential (990 mV vs SCE), thus showing virtually no reactivitytoward O2. On the other hand, the metal centers of the dinuclear and trinuclear copper(I) complexes, 3 and 4,exhibit a distorted trigonal planar geometry and a trigonal pyramidal geometry, respectively. In contrast to themononuclear copper(I) complexes, these dinuclear and trinuclear copper(I) complexes reacted with O2 to inducean aromatic ligand hydroxylation reaction involving an NIH-shift of one of the ethyl substituents on the benzenespacer. The NIH-shift of the alkyl substituent on the aromatic ring is strong evidence of the electrophilic aromaticsubstitution mechanism, although the active oxygen intermediate could not be directly detected during the courseof the reaction. The biological relevance of the copper(I) complexes is also discussed on the basis of structure andO2-reactivity.