A strategy to improve the performance of cerium(iii) photocatalysts

A structural modification strategy to improve the photocatalytic performance of a series of cerium(iii) bis(guanidinate) mono(amide) molecular luminophores was demonstrated. Reducing the steric bulkiness of the amide ligand gave rise to two categories of complexes with distinct photophysical and photochemical properties. A structural parameter, the amide cone angle (), was applied to differentiate the two categories. Complexes with smaller cone angles ( < 156 degrees, category B) exhibited more reducing potentials and faster electron-transfer rates than those of complexes with larger cone angles ( > 173 degrees, category A). And only complexes in the category B could achieve the photocatalytic phenylation of an aryl bromide. These results demonstrated that reducing the steric bulkiness of the amide ligand improved the performance of cerium(iii) bis(guanidinate) mono(amide) photocatalysts in a systematic manner.