There is little that is known about organic dye aggregates because the size and geometry are difficult to control. This further complicates the comparison of the optical properties of the dye aggregate to its structure. The purpose of this research was to synthesize simple face to face organic dye aggregates and study their solubility and optical absorbance, and compare those results with the results of structurally similar dyes. Using a monomer that has been shown to readily form aggregates, complex dimer molecules were synthesized. The two monomer chains were connected via alkane chains of piperazine, which put a space of two carbons between each monomer chain. Each dye aggregate was in contact with another dye aggregate in a dilute solution, which permitted the comparison of single interactions and the resulting optical properties. The face to face dimer showed a lower energy, red shift in its optical absorbance when compared to that of the monomer. Molecula!
r orbital calculations were carried out on the aggregate and the geometry and the distance between the atoms was obtained. The molecular orbital calculations showed an uncharacteristic non-pi stacking between the atoms of the face to face dye.
Stephanie Terry, ’02 Aurora, CO
Major: Biochemistry and Spanish
Sponsor: Charley Liberko