Resumen de Energy Transfer Photocatalytic (E) → (Z) Isomerization of 2-Nitrocinnamaldehyde using an Inexpensive, 3-D Printed Photoreactor Monitored by 1H NMR Spectroscopy and Computational Modeling

Philip P. Lampkin, Angie E. Xu, Brian J. Esselman, Cara E. Schwarz, Sebastian D. Thompson, Samuel H. Gellman, Nicholas J. Hill

• Synthesis of (Z)-alkenes is challenging because the (E) stereoisomers are usually more stable. Energy transfer photocatalysis has emerged as an efficient strategy for (E) → (Z) alkene isomerization. We report the development of an advanced undergraduate laboratory experiment that introduces students to contemporary organic photocatalysis methods and theory within the context of the energy transfer photocatalyzed (E) → (Z) isomerization of 2-nitrocinnamaldehyde. Students assess the ability of the photocatalysts [Ru(bpy)3][PF6]2 and [TPP][BF4] to promote substrate isomerization, monitor and analyze reactions by 1H NMR spectroscopy, and probe the isomerization mechanism via computational chemistry. This work uses the Wisconsin Photoreactor Platform, a source of affordable, readily fabricated, and reliable photoreactors.