Covalency Driven Preservation of Local Charge Densities in a Metal to Ligand Charge Transfer Excited Iron Photosensitizer

Covalency is found to even out charge separation after photo amp; 8208;oxidation of the metal center in the metal amp; 8208;to amp; 8208;ligand charge amp; 8208;transfer state of an iron photosensitizer. The amp; 963; amp; 8208;donation ability of the ligands compensates for the loss of iron 3d electronic charge, thereby upholding the initial metal charge density and preserving the local noble amp; 8208;gas configuration. These findings are enabled through element amp; 8208;specific and orbital amp; 8208;selective time amp; 8208;resolved X amp; 8208;ray absorption spectroscopy at the iron L amp; 8208;edge. Thus, valence orbital populations around the central metal are directly accessible. In conjunction with density functional theory we conclude that the picture of a localized charge amp; 8208;separation is inadequate. However, the unpaired spin density provides a suitable representation of the electron hole pair associated with the electron amp; 8208;transfer proces