Source: Laboratory of Dr. Henrik Sundén - Chalmers University of Technology Nuclear magnetic resonance (NMR) spectroscopy is a vital analysis technique for organic chemists. With the help of NMR, the work in the organic lab has been facilitated tremendously. Not only can it provide information about the structure of a molecule but also determine the content and purity of a sample. Compared with other commonly encountered techniques for organic chemists - such as thermal analysis and mass spectrometry (MS) - NMR is a non-destructive method that is valuable when recovery of the sample is important. One of the most frequently used NMR techniques for an organic chemist is proton (1H) NMR. The protons present in a molecule will behave differently depending on its surrounding chemical environment, making it possible to elucidate its structure. Moreover, it is possible to monitor the completion of a reaction by comparing NMR spectra of the starting material to that of the final product. This video exemplifies how NMR spectroscopy can be used in the everyday work of an organic chemist. The following will be shown: i) preparation of an NMR sample. ii) Using 1H NMR to monitor a reaction. iii) Identifying the product obtained from a reaction with 1H NMR. The reaction that will be shown is the synthesis of an E-chalcone (3) from an aldehyde (1) and a ketone (2) (Scheme 1).1 Scheme 1. Synthesis of (2E)-3-(4-methoxyphenyl)-1-(4-methylphenyl)-2-propen-1-one.