The Discovery Approach to NMR: Development of Chemical-Shift Additivity Tables and Application to Product Identification

Abstract

A discovery-based approach to the preparation and application of chemical-shift additivity tables is presented to give students insight into the development of NMR spectral prediction software. The chemical shift of each proton in meta-dinitrobenzene is first assigned on the basis of the expected coupling constants (ortho, meta, and para) around a benzene ring. These chemical shifts are used to determine the chemical shift additivity for a nitro group ortho, meta, or para to hydrogen on a benzene nucleus. The chemical shift additivities obtained are then used to predict the NMR spectrum of the product of nitration of methylbenzoate.