Spin—spin couplings between ¹³C nuclei in five‐membered heteroaromatic ring systems

Abstract

Abstract A set of 14 1 J (CC) spin—spin coupling constants are reported for 11 five‐membered heteroaromatic molecules, including all relevant diazole, triazole, oxazole, oxadiazole, thiazole and thiadiazole systems. The couplings show a clear distinction between carbon—carbon bonds which are formally double or single, respectively. There seems to be no correlation of the couplings with the bond lengths concerned, in spite of some apparent trends. Potential applications of the couplings are discussed in assessing the aromaticity of five‐membered heterocycles.