Using Donor-Acceptor Stenhouse Adducts to Teach Photochromism in the Undergraduate Laboratory

There has been dramatic growth in interest and research regarding organic photochromism in recent decades. Despite this, the topic is seldom addressed in the undergraduate chemistry curriculum. Herein, we present a straightforward and robust experiment for the second semester organic chemistry laboratory curriculum which combines multistep synthesis, photochromism, and optical characterization. Over the course of a three-step synthesis, students prepare both the open and closed isomers of a Donor-acceptor Stenhouse adduct. At each stage of the synthesis, the pure products are isolated by filtration and characterized by traditional means (FTIR, H-1 NMR). Additionally, students collect UV-vis data on the photoisomerization process and use this to calculate kinetic parameters. An inquiry-based variant of the experiment is also presented.

Automated summary

This experiment introduces a straightforward and robust approach for undergraduate students to explore organic photochromism through multistep synthesis, optical characterization, and UV-vis data analysis. Students can isolate and characterize pure products at each stage of the synthesis, while also calculating kinetic parameters based on the collected data. An inquiry-based variant of the experiment is also provided for further exploration and understanding.