Universität Heidelberg, Anorganisch-Chemisches Institut und Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), INF 270, 69120, Heidelberg, Germany.
Department of Chemistry and Nano Science, Ewha Womans University, Seoul, 120-750, Korea.
Angew Chem Int Ed Engl. 2016 Sep 5;55(37):11129-33. doi: 10.1002/anie.201605099. Epub 2016 Jul 28.
For a series of Fe(IV) =O complexes with tetra- and pentadentate bispidine ligands, the correlation of their redox potentials with reactivity, involving a variety of substrates for alkane hydroxylation (HAT), alkene epoxidation, and phosphine and thioether oxidation (OAT) are reported. The redox potentials span approximately 350 mV and the reaction rates over 8 orders of magnitude. From the experimental data and in comparison with published studies it emerges that electron transfer and the driving force are of major importance, and this is also supported by the DFT-based computational analysis. The striking difference of reactivity of two isomeric systems with pentadentate bispidines is found to be due to a destabilization of the S=1 ground state of one of the ferryl isomers, and this is supported by the experimentally determined redox potentials and published stability constants with a series of first-row transition metal ions with these two isomeric ligands.
报道了一系列具有四齿和五齿双吡啶配体的 Fe(IV) = O 配合物，其氧化还原电位与其反应性相关，涉及烷烃羟化（HAT）、烯烃环氧化和膦及硫醚氧化（OAT）的各种底物。氧化还原电位跨度约为 350 mV，反应速率跨越 8 个数量级。从实验数据和与已发表的研究相比，电子转移和驱动力非常重要，这也得到了基于密度泛函理论的计算分析的支持。具有五齿双吡啶的两个异构体系的反应性的显著差异归因于一个费罗铁异构体的 S=1 基态的不稳定，这得到了实验确定的氧化还原电位和与一系列具有这两个异构配体的第一过渡金属离子的发表的稳定常数的支持。
