2H1C Mimicry: Bioinspired Iron and Zinc Complexes Supported by N,N,O Phenolate Ligands

Abstract

In pursuit of mimicking the ubiquitous 2H1C motif in mononuclear non-heme iron enzymes, two new bioinspired N,N,O phenolate ligands, BenzImNNO and ImPh2NNO, are synthesised and their coordination chemistry with zinc(II) and iron(II) is explored. BenzImNNO coordinates by means of an anionic κ3-N,N,O donor set and readily forms homoleptic bisligated complexes, also in the presence of equimolar amounts of metal salt. In contrast, the increased steric bulk of ImPh2NNO promotes the formation of dinuclear complexes, [M2(ImPh2NNO)2(OTf)2] (M=Fe, Zn), with facially opposing metal sites, as a result of its unique bridging μ2:κ2-N,N:κ1-O coordination mode. We investigate the robustness of the ligand's dinucleating coordination mode during oxidative transformations and demonstrate that its coordination mode is retained upon triflate substitution for a biorelevant thiophenolate co-ligand.