Synthesis and Luminescence and Ionochromic Properties of 9-Hydroxy-1-methyl-3-oxo-3H-benzo[f]chromene8-carbaldehyde Imines and Hydrazones

摘要

Formylation of 9-hydroxy-1-methyl-3H-benzo[f]chromen-3-one with hexamethylenetetramine in acetic acid afforded 9-hydroxy-1-methyl-3-oxo-3H-benzo[f]chromene-8-carbaldehyde which was converted to the corresponding aldehyde imines and aroylhydrazones. According to the H-1 NMR and UV spectral data, 9-hydroxy-1-methyl-3-oxo-3H-benzo[f]chromene-8-carbaldehyde imines in solution exist as ketone tautomers, whereas its aroylhydrazones have enol structure. 9-Hydroxy-1-methyl-3-oxo-3H-benzo[f]chromene-8-carbaldehyde aroylhydrazones are multifunctional ionochromic compounds capable of forming colored complexes with d metal cations, as well as with fluoride, cyanide, and acetate anions. The complexation leads to switching of the absorption and fluorescence properties of the initial compounds. Metal cations cause naked-eye visible change of the solution color from colorless to bright orange and fluorescence quenching, whereas in the presence of anions the color changes to red in combination with a red shift and increase in the emission intensity.