The interaction of triplet excited state ketones with copper(II) complexes: effects of β-diketonate ligands

The copper(II) complexes of acetylacetone, 1,1,1-trifluoroacetylacetone and 1,1,1,5,5,5-hexafluoroacetylacetone quench the triplet excited state benzophenone efficiently with about equal rate constants. However, the limiting quantum efficiency of the photoreduction increases with increasing number of CF₃ groups in the complexes or with increasing hydrogen-atom-donating ability of the solvent.