Photochemistry is a novel field of science in which substances absorb photons as the source of energy and photoreact. Ultraviolet light, which contains high-energy photons, is one of the few spectral regions that photochemists work with. All photoreactions in this study were carried out using an inexpensive commercially available UV source, intended for curing fingernail polish, instead of its widely-used and costly counterpart employed in current photochemistry literature.
Our research was centered on the purification and photoisomerization of a photoreactive compound: 1,2-bis(4-pyridyl)ethylene (BPE). BPE was synthesized using a cost-effective method previously developed at Cornell. The obtained dark crude product was purified by recrystallization from water and sublimation.
The more stable trans-BPE was converted to the less stable cis-BPE in this study by photoisomerization. The pure trans-BPE was first dissolved in acetonitrile and photoisomerized under UV light to give an 80/20 cis/trans mixture, and the cis-isomer was isolated by selective precipitation of trans-BPE through the addition of excess 2,7-dihydroxynaphthalene (DHN) followed by an acid-base extraction to remove the excess DHN. All the products involved in the research were identified through 1H NMR spectroscopy.
Jihang Wang, ’15
Majors: Chemistry with ACS Certification, Biochemistry and Molecular Biology
Sponsor: Charles Liberko