Institut de Recherches sur la Catalyse et l'Environnement de Lyon, Unité Mixte de Recherche 5256, Centre National de la Recherche Scientifique, Université Lyon 1, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex, France.
Nat Chem. 2012 Dec;4(12):1024-9. doi: 10.1038/nchem.1471. Epub 2012 Oct 14.
High-valent oxo-metal complexes are involved in key biochemical processes of selective oxidation and removal of xenobiotics. The catalytic properties of cytochrome P-450 and soluble methane monooxygenase enzymes are associated with oxo species on mononuclear iron haem and diiron non-haem platforms, respectively. Bio-inspired chemical systems that can reproduce the fascinating ability of these enzymes to oxidize the strongest C-H bonds are the focus of intense scrutiny. In this context, the development of highly oxidizing diiron macrocyclic catalysts requires a structural determination of the elusive active species and elucidation of the reaction mechanism. Here we report the preparation of an Fe(IV)(µ-nitrido)Fe(IV) = O tetraphenylporphyrin cation radical species at -90 °C, characterized by ultraviolet-visible, electron paramagnetic resonance and Mössbauer spectroscopies and by electrospray ionization mass spectrometry. This species exhibits a very high activity for oxygen-atom transfer towards alkanes, including methane. These findings provide a foundation on which to develop efficient and clean oxidation processes, in particular transformations of the strongest C-H bonds.
高价氧合金属配合物参与选择性氧化和去除外来化合物的关键生化过程。细胞色素 P-450 和可溶性甲烷单加氧酶的催化特性分别与单核铁血红素和双核非血红素平台上的氧物种有关。受这些酶氧化最强的 C-H 键的迷人能力启发的仿生化学系统是人们关注的焦点。在这种情况下，开发具有强氧化性的双核大环催化剂需要确定难以捉摸的活性物种的结构，并阐明反应机制。在这里，我们报道了在-90°C下制备 Fe(IV)(µ-亚硝基)Fe(IV)=O 四苯基卟啉阳离子自由基物种，通过紫外-可见、电子顺磁共振和穆斯堡尔光谱以及电喷雾电离质谱进行了表征。该物种对烷烃（包括甲烷）的氧原子转移具有很高的活性。这些发现为开发高效、清洁的氧化工艺，特别是最强的 C-H 键转化，提供了基础。
