Steric and Electronic Modulation of Iron Complexes via Chalcogen Atom Substitution in the Secondary Coordination Sphere

The secondary coordination sphere surrounding metal centers has been shown to have a regulatory effect on the structure and function of metal complexes. In this study, we report the preparation of Fe complexes supported by a new tripodal ligand N , N ′, N ″‐[nitrilotris(ethane‐2,1‐diyl)]tris( P , P ‐diphenylthiophosphinic amido) ([psat] 3– ) that features thiophosphinic (PS) amido groups. This ligand was designed to evaluate the effect of chalcogen substitution on the coordination chemistry of iron complexes when compared to analogous species that have been previously reported with the phosphinic (PO) amido ligand system, N , N ′, N ″‐[nitrilotris(ethane‐2,1‐diyl)]tris( P , P ‐diphenylphosphinic amido) ([poat] 3– ). Although this variation had minimal impact on the structural and electronic properties of Fe(II) centers, their oxidative chemistry was found to be different, which isattributed to change in the chalcogen atoms within the secondary coordination sphere.