Computational and experimental studies into NMR characterization of [2+2] cycloaddition products of norbornene

► The geometry of six stereoisomers of pentacyclotetradecane was optimized at the DFT level. ► This is the first study of the [2+2] dimers of norbornene by the DFT theoretical method. ► The calculated 1H and 13C chemical shifts (δ) were compared with those obtained experimentally. ► The calculated chemical shifts were found to be in good agreement with the experimental data. ► The experimental 13C NMR data of the [2+2] norbornene dimers are presented for the first time.