Visible-Light Excitation of Infrared Lanthanide Luminescence via Intra-Ligand Charge-Transfer State in 1,3-Diketonates Containing Push-Pull Chromophores

A new 1,3-diketonato ligand containing both an electron-donor [4-(dimethylamino)benzene] and an electron-acceptor (4- nitrobenzene) group and its lanthanide complexes have been prepared. They display an intense intra-ligand charge-transfer absorption transition in the visible region of the spectrum at 400–550 nm which was utilized to achieve visible-light excitation of metal-centred infrared luminescence of NdIII, ErIII and YbIII ions.