Photoredox reactivity of copper(II)-3,5-diisopropylsalicylate induced by ligand-to-metal charge transfer excitation of the copper-phenolate chromophore

The electronic spectrum of CuII(dps)2 in CH3CN with dps=3,5-diisopropylsalicylate shows a ligand field absorption at λmax=711 nm (ε=140 M−1 cm−1), and a phenolate to Cu(II) ligand-to-metal charge transfer (LMCT) band at λmax=428 nm (ε=950). LMCT excitation of CuII(dps)2 leads to the reduction of Cu(II) to Cu(I). Copper(II) disappears with φ=2.8×10−3 at λirr=436 nm.