Towards longer-lived metal-to-ligand charge transfer states of iron(II) complexes: an N-heterocyclic carbene approach

A 9 ps (MLCT)-M-3 lifetime was achieved by a Fe-II complex based on C(NHC)boolean AND N(py)boolean AND C(NHC) pincer ligands. This is the longest known so far for any kind of complexes of this abundant metal, and increased by almost two orders of magnitude compared to the reference Fe-II bis-terpyridine complex.