Two sets of bio-inspired non-heme iron complexes, each comprising of an Fe^II and Fe^III species, bearing 16-membered macrocyclic tetradentate N–heterocyclic carbene ligands are reported. The complexes exhibit trans labile coordination sites, are characterized by means of NMR, ESI-MS, elemental analysis, SC-XRD and cyclic voltammetry and assessed as olefin epoxidation (pre–)catalysts applying H₂O₂ as oxidant. Sc(OTf)₃ and AcOH are evaluated as Lewis and Brønsted acidic additives, respectively, resulting in partially noticeable improvement in catalytic performance. Hereby, complex 2b shows high stability (TON = 1,000 at 20 °C), high temperature tolerance and advances in the more challenging epoxidation of terminal and functionalized olefins. Furthermore, in-depth DFT calculations are conducted to put the catalysts’ structural and electronic features into relation with the catalytic results.

据报道，有两组生物启发的非血红素铁配合物，每一个都由一个Fe ^II和Fe ^III物种组成，带有16元大环四齿N-杂环卡宾配体。配合物表现出反式不稳定配位点，其特点是NMR，ESI-MS，元素分析，SC-XRD和循环伏安法的装置和评定为烯烃环氧化（预）催化剂施加ħ ₂ ö ₂作为氧化剂。Sc（OTf）₃和AcOH分别被评价为路易斯和布朗斯台德酸性添加剂，从而在催化性能方面产生了部分明显的改善。特此，复数2b具有高稳定性（在20°C下TON = 1,000），高温耐受性以及在末端烯烃和官能化烯烃更具挑战性的环氧化方面取得的进展。此外，进行了深入的DFT计算，以将催化剂的结构和电子特征与催化结果联系起来。