Design and Characterization of Photo-responsive Supramolecular Aggregates

A supramolecular assembly is a complex of molecules held together by noncovalent interactions. The process by which supramolecular assemblies are formed is called “molecular self-assembly”, during which the molecules spontaneously aggregate in a specific manner, acquiring new properties. Incorporating photoisomerizable molecules into supramolecular assemblies offers considerable opportunities in developing new smart materials. Using UV-Vis and CD spectroscopy, we explored the propensity for a dicarboxylic acid derivatized azobenzene photoswitch (ADA) to form supramolecular aggregates and investigated the photochemical behavior of the system. ADA was shown to undergo cis-trans isomerization when irradiated in aqueous solution with visible and UV light. Upon reduction of the pH, the trans form of ADA aggregates in a chiral fashion. Homo-aggregation of the trans form of ADA was shown to prevent photoisomerization to the cis form. The feasibility of forming supramolecular heteroaggregates between ADA and other molecules, including water soluble porphyrins and poly (glutamic acid), was explored.https://ecommons.udayton.edu/stander_posters/1422/thumbnail.jp