Intrusive Learning Accompanying Knowledge Transfer During Organic Chemistry Laboratory Experiment: Synthesis, Characterization, and Photoisomerization of α-Cyanostilbenes

Discussion-based outcomes of organic chemistry laboratory experiments form a powerful tool to create a learning environment, facilitate teamwork, and build scientific skills and analytical ability for undergraduate science students. A Knoevenagel-type condensation reaction was selected to demonstrate these results by taking phenylacetonitrile and four different aldehydes as reactants to form alpha-cyanostilbenes. The reactions were performed under almost neat conditions open to air at room temperature. The short duration (2-20 min) and visual solid product formation also make the experiment attractive. Melting points, TLC, FTIR, UV-vis, and GC-MS were utilized to characterize and check the purity of the products. Photoisomerization studies were performed in sunlight. Substituent effects in the IR stretching frequency, UV-vis spectra, and photoisomerization behavior create a platform for group discussion and knowledge transfer.