A multicolor Organic Chemistry laboratory experiment involving synthesis of a single dye is the highlight of this experiment. This experiment is one of the most discussed labs among undergraduate students at Plymouth State University. In first laboratory period, students synthesize a solvatochromic dye by nucleophilic attack of a carbanion on an aldehyde carbonyl group. This is a great way to introduce carbonyl chemistry and synthesis to students. During the reflux period, the dipole moments of seven solvents are calculated using Spartan computational program. The dye is recrystallized and yield is calculated. Following week, students prepare brightly colored solutions of dye using the same seven solvents. Each solvent displays amazingly different colors due to stabilization or destabilization of ground and excited states. Complimentary colors of each solution are identified using simple color wheel. Using UV-Visible spectroscopy, wavelength of maximum absorption (λ<sub>max</sub>) are determined. Students discover the relation between dipole moment and λ<sub>max. </sub>Additional spectroscopic techniques are used for structure determination.This visually stimulating experiment proved effective for triggering students’ curiosity about solvation and colors in the laboratory.

Thought-provoking colorful sophomore organic chemistry laboratory experiment

255th National Meeting (2018)

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