¹³C,¹³C coupling constants from a mixture of isotopomers (¹³C) of substituted aromatic compounds; 1‐nitronaphthalenes

13C Homonuclear decoupling experiments led to the assignment of the carbon‐carbon coupling constants of 13C‐enriched 1‐nitronaphthalene obtained by nitration of [1‐13C]naphthalene. The effects of substituents on coupling constants can be explained on the basis of the electronegativity of the first atom of the substituent, and the observed substituent effects are shown to be parallel to previous data for oxygen containing substituents.