Date of Award

Spring 2000

Document Type

Restricted Thesis

Terms of Use

© 2000 Thalia Mills. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Physics & Astronomy Department

First Advisor

Peter J. Collings


The spectroscopic and light scattering techniques for studying the size and shape of aggregates, which previously have been tested extensively on porphyrins, were applied to two novel systems: (1) an octahedral complex of cobalt(II) and 4-(5-chloro-2-pyridylazo)-m-phenylenediamine (5-CIPADAB) which aggregates on a DNA template and (2) dilute solutions of the self-aggregating compound bis(2-N, N-diethylamine-ethyl)perylene-3,4,9, 10-tetracarboxylic diimide (Compound Z), which is a liquid crystal at high concentrations. A significant shift in the extinction spectrum with aggregation was observed for both systems. A resonance light scattering peak at 545 nm was observed for the Co(II)/5-CI-PADABIDNA system, but for the compound Z system significant scattering was only observed in aqueous solutions of a hydrochloride salt of compound Z which had precipitated. Fluorescence interfered with scattering in solutions of compound Z. Scattering experiments indicate that the size of the aggregates observed in both systems is on the order of 1 μm, similar to the size of porphyrin aggregates reported previously. The scattering for both systems was significantly less than that observed for porphyrins, making light scattering techniques difficult to use.