Abstract
We describe a study of the influence of amine-containing ligands on the photoredox-relevant properties of Eu(II) toward the rational design of Eu(II)-containing catalysts for visible-light-promoted photoredox reactions. We report our observations of the effects of the degree of functionalization of amines, denticity, and macrocylic ligands on the absorbance of Eu(II). Ligands that contain secondary amines bathochromically shift the absorbance of EuCl(2) relative to ligands that contain primary or tertiary amines. Similarly, ligands of larger denticity have a larger bathochromic shift of the absorbance than ligands of smaller denticity. We observed that macrocyclic ligands have a larger effect on the absorbance of EuCl(2) than nonmacrocyclic ligands. Also, we report the photoredox reactivity of four new Eu(II)-containing complexes. These observations are potentially influential in understanding the ligand properties that promote the use of Eu(II) in visible-light-promoted photoredox catalysis.