Janus-type emission from a cyclometalated iron(iii) complex

<jats:title>Abstract</jats:title><jats:p>Although iron is a dream candidate to substitute noble metals in photoactive complexes, realization of emissive and photoactive iron compounds is demanding due to the fast deactivation of their charge-transfer states. Emissive iron compounds are scarce and dual emission has not been observed before. Here we report the Fe<jats:sup>III</jats:sup> complex [Fe(ImP)<jats:sub>2</jats:sub>][PF<jats:sub>6</jats:sub>] (HImP = 1,1′-(1,3-phenylene)bis(3-methyl-1-imidazol-2-ylidene)), showing a Janus-type dual emission from ligand-to-metal charge transfer (LMCT)- and metal-to-ligand charge transfer (MLCT)-dominated states. This behaviour is achieved by a ligand design that combines four <jats:italic>N</jats:italic>-heterocyclic carbenes with two cyclometalating aryl units. The low-lying <jats:italic>π</jats:italic>* levels of the cyclometalating units lead to energetically accessible MLCT states that cannot evolve into LMCT states. With a lifetime of 4.6 ns, the strongly reducing and oxidizing MLCT-dominated state can initiate electron transfer reactions, which could constitute a basis for future applications of iron in photoredox catalysis.</jats:p>