The synthesis and proton-induced spectral switching of a novel azine dye and its boron complex

An azine dye and its boron complex were synthesized and their structures were confirmed using elemental analysis, UV–Vis, fluorescence, mass and 1H NMR spectroscopic techniques. The effects of protonation/deprotonation on the absorption and emission characteristics of the two dyes were determined. The observed effects of pH upon the colour of the dyes were interpreted in terms of electron density distribution and intramolecular charge transfer.