A Coordination Network with Ligand‐Centered Redox Activity Based on facial‐[CrIII(2‐mercaptophenolato)3]3− Metalloligands

The design of redox-active metal-organic frameworks and coordination networks (CNs), which exhibit metal- and/or ligand-centered redox activity, has recently received increased attention. In this study, the redox-active metalloligand (RML) [Me4N]3fac-[CrIII(mp)3] (1) (mp = 2-mercaptophenolato) was synthesized and characterized by single-crystal X-ray diffraction analysis, before its reversible ligand-centered one-electron oxidation was examined by cyclic voltammetry and spectroelectrochemical measurements. As complex 1 contains OS coordination sites in three directions, complexation with K+ ions led to the formation of a two-dimensional honeycomb sheet-structured [K3fac-{CrIII(mp)3}(H2O)6]n (2·6H2O), which is the first example of a redox-active CN constructed from a RML with o-disubstituted benzene ligands. Herein, we unambiguously demonstrate the ligand-centered redox activity of the RML, which is incorporated in the redox-active CN 2·6H2O in the solid state.