Maria Fonseca

Maria Fonseca

“Photoisomerization and Thermal Isomerization of Azobenzene Derivatives”

Maria Fonseca, Mihael Gerkman, Alejandra Gonzalez, Grace Han
University of Massachusetts, Lowell / Chemical Engineering
Hosted by Han's Lab


Azobenzene (AB) is a light responsive molecule that can be switched between two distinct conformations. Exposing azobenzene to UV light will generate a high energy photoisomer (cis), which can be converted back to the parent molecule (trans) by shining visible light or applying heat. The ability to control molecular structure and spatial arrangement using light has motivated new photoresponsive materials where AB is linked with polymers, nanoparticles or DNA. We characterized the switching ability of new AB derivatives to determine under what conditions switching occurs and the thermal stability of the cis isomer through absorption and 1H NMR spectroscopy.

Understanding the correlation between the molecular structure and isomerization characteristics provides insight into the molecular design strategy for controlling photo and thermal isomerization behaviors. This will help identify AB structures that undergo efficient switching using visible light, are thermally stable, and yield a large conversion to the cis isomer. AB derivatives with these exceptional qualities can provide novel opportunities for external control of materials.


Brandeis University Chemistry Department