In this study, a simple and quick hands-on activity is designed to introduce students from different levels and backgrounds in chemistry to plant dyeing. In this approach, most plant dyes are compatible with the mordant dyeing method, which is fundamentally based on complexation reactions. Specifically, metal ions in the mordant interact with functional groups such as −OH, −COOH, and −NH2 present in both the dyes and the fibers through coordination bonds. This interaction leads to the formation of coordination structures (metal ions–dyes or fibers–metal ions–dyes), which enhance dye uptake. Moreover, the formation of complexes between metal ions and natural dyes alters the energy levels associated with electron transitions and modifies the distribution of the π-electron cloud. These changes result in shifts in absorption wavelengths and color changes, thereby producing distinct colors. The simplicity and educational impact of this activity make it an effective tool for introducing fundamental concepts in coordination chemistry and spectroscopic behavior, particularly in undergraduate education.
Shen et al. (Tue,) studied this question.