Chemistry Letters, Vol.44, No.12, 1703-1705, 2015
Indolylindolinone: Easily Accessible, Tunable, and Wide-range Absorbing Dyes
Dehydrative coupling between indoles and isatins provided indolylindolinones in good yields as novel dyes with wide-range absorption due to intramolecular charge-transfer interactions. The HOMO and LUMO levels of indolylindolinones could be manipulated individually by the introduction of substituents on the indole and isatin units, respectively. Indolylindolinones served as a bidentate ligand to Ni(II) and Cu(II) ions to provide stable metal complexes. Metal coordination induced large bathochromic shift of the lowest-energy absorption band to the near-infrared region.