Ruthenium(II) Tris(2,2′-bipyridyl) Complex Incorporated in UiO-67 as Photoredox Catalyst

Ruthenium(II) bis(2,2'-bipyridine) (2,2'-bipyridyl-5,5'-dicarboxylic acid), Rudcbpy, attached to the UiO-67(Zr) metal organic framework (MOF), generates upon visible light excitation the localized triplet excited state of the ruthenium(II) bipyridyl complex that decays partly to a very long-lived (millisecond time scale) photoinduced charge-separated state following a similar behavior as that of analogous ruthenium(II) tris(bipyridyl) complex dissolved in water, except that the lifetime of the soluble complex excited state is orders of magnitude shorter. The occurrence of photoinduced charge separation on the Rudcbpy-UiO-67(Zr) MOF has been proven visually by using methyl viologen as electron acceptor. Rudcbpy-UiO-67(Zr) behaves as a heterogeneous, reusable, photoredox catalyst promoting debromination of alpha-bromoketones with excellent selectivity at high conversions. Characterization data show that Rudcbpy-UiO-67(Zr) is stable under the photocatalytic reaction conditions.