Azo-hydrazone tautomerism by in situ Cu~(II) ion catalysis and complexation with the H2O2 oxidant of CI. Disperse Yellow 79

摘要

A novel dinuclear copper(II) complex 2 bearing double μ2-oxo bridges has been obtained by in situ Cu~(II) ion catalysis and complexation with the H2O2 oxidant of CI. Disperse Yellow 79 (1), where a new dia-nionic ligand is in situ formed having an additional phenolic group and it coordinates with the central Cu" ion as a tridentate chelating ligand. Furthermore, both of the starting material 1 and the final neutral dye-metal product 2 have been structurally and spectrally characterized and compared, where azo-hydrazone tautomerism has been observed before and after metal-ion complexation. To the best of our knowledge, this is the first structural report about the heterocyclic dyes having quinoline-2,4-dione skeleton and the corresponding azo-hydrazone tautomerism between them.