Branching mechanism of photoswitching in an Fe(II) polypyridyl complex explained by full singlet-triplet-quintet dynamics

Abstract

The description of full singlet-triplet-quintet dynamics is challenging due to the need for simultaneous treatment of disparate spin states, as well as multidimensional dynamics. Here the authors report a branching mechanism for the Fe(II) polypyridine complex [Fe(terpy)2]2+ by full-dimensional simulation of singlet-triplet-quintet dynamics, showing that the quintet (5MC) state is populated on the sub-ps timescale by two sequential 3MLCT→3MC→5MC pathways involving the two 3MC components 3T1g and 3T2g.