Goldberg David P
The Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
Acc Chem Res. 2007 Jul;40(7):626-34. doi: 10.1021/ar700039y. Epub 2007 Jun 21.
The activation of dioxygen and its analogues, such as hydrogen peroxide, by metalloporphyrins leads to the generation of high-valent metal-oxo species. This process is critically important to heme-catalyzed reactions, such as for cytochrome P450, and synthetic porphyrin-catalyzed oxidations. We have synthesized a new ring-contracted porphyrinoid system called a corrolazine that is designed to stabilize high oxidation states, including high-valent metal-oxo species. The corrolazine ligand stabilizes manganese(V) terminal oxo and terminal imido complexes for isolation, both of which are only transiently observed with normal porphyrin macrocycles. Examination of both oxygen atom transfer and hydrogen atom abstraction reactions for the Mn(V)-oxo complex has led to a number of mechanistic insights regarding these transformations. The activation of H 2O 2 to give the Mn(V)-oxo complex exhibits some dramatic and unexpected axial ligand effects that call into question the normal role of axial ligands in O-O bond cleavage pathways.
金属卟啉对双氧及其类似物（如过氧化氢）的活化会导致高价金属-氧物种的生成。这一过程对于血红素催化的反应（如细胞色素P450）以及合成卟啉催化的氧化反应至关重要。我们合成了一种名为咕嗪的新型缩环卟啉类体系，其设计目的是稳定包括高价金属-氧物种在内的高氧化态。咕嗪配体可稳定锰（V）末端氧和末端亚胺配合物以便分离，而在正常的卟啉大环中只能短暂观察到这两种配合物。对锰（V）-氧配合物的氧原子转移和氢原子夺取反应的研究，已得出了关于这些转化的一些机理见解。H₂O₂活化生成锰（V）-氧配合物表现出一些显著且意想不到的轴向配体效应，这对轴向配体在O - O键断裂途径中的正常作用提出了质疑。
