MOED, a merocyanine dye, has been found not only to be solvatochromic (changes color in varying solvents), but thermochromic (color is temperature dependent), aggregate-forming (forms dimers), and an acid-base indicator as well. In this study, a derivative of MOED was synthesized by replacing the picolinium ring with a quinolinium ring. The change in the absorption of light by the derivative in varying solvents was predicted to be red-shifted and this was confirmed by UV-Vis. However, the pH dramatically affected the absorption of the light in water. In the process of determining the pKa of the derivative, substantial color changes were noted in varying concentrations of the dye in methanol. Upon heating of a relatively concentrated solution, the color of the solution changed from red to deep purple and back again once cooled to room temperature. After cooling in an ice bath, the solution then turned yellow and back again to red at room temperature. These thermochromic and aggregate forming properties are currently being investigated further. However, it appears that the derivative of MOED exhibits the same four properties that MOED does and, in some cases, to a much greater extent.
Jessica Allison, ’04 Springfield, IL
Major: Biochemistry and Molecular Biology
Sponsor: Charles Liberko