Studies of 13C13C coupling constants. IV. The isopropenyl system

Abstract 13 C 13 C coupling constants were obtained on ten monolabeled or dilabeled isopropenyl compounds, using repetitive cw methods. The single-bond and double-bond couplings were found to vary over 10 and 14 Hz, respectively, throughout the series. The results were analyzed in terms of INDO calculations, which indicate a relationship between J cc values and −I + substituent character. Both experimental and INDO results are considered in comparison to previously reported data on ethyl and acetyl compounds.