NMR-Challenge.com: Exploring the Most Common Mistakes in NMR Assignments

Abstract

NMR spectroscopy is the most powerful tool for determining the structures of chemicals. It is applied in a broad range of scientific disciplines, including physics, structural biology, material science, medicine, and chemistry. Interpreting NMR spectra is part of the core skill set mainly of organic chemists. In 2022 we introduced the educative website NMR-Challenge.com presenting 200 spectral tasks of various difficulties. The website collected more than 428,000 submitted solutions over 20 months and thus provides the largest data set of responses to NMR assignments. By analyzing the structures submitted by users of the website, we identified patterns of the most common mistakes, which might be useful in devising new teaching strategies. Here, we present three case studies of the most common sources of spectral misinterpretation-recognition of the structures of isomeric esters, determination of substitution positions in disubstituted benzenes, and recognition of intramolecular hydrogen bonding in 1H spectra-based on more than 28,000 answers collected at NMR-Challenge.com and recommend how to amend the frontal teaching about these problems.