Abstract: Transition-metal complexes are widely used as photosensitizers and photocatalysts, and in light-emitting devices [Chem. Rev. 117, 10940 (2017)]. We have recently demonstrated first iron complex [FeIII(btz)3]3+ exhibiting room temperature photoluminescence from a charge transfer state and show that it has a 100 ps excited state charge transfer lifetime which is unprecedented for any iron complex [Nature 543, 695 (2017)]. This was characterized as a rare low-spin FeIII d5 complex with emission from a long-lived doublet ligand-to-metal charge transfer (2LMCT) state. Absence of...
