³⁵Cl/³⁷Cl one‐bond isotope effects on ¹³C chemical shifts in a series of para‐substituted chlorobenzenes

One‐bond isotope shifts of ³⁵Cl/³⁷Cl natural abundance chlorine isotopomers were measured in the 75.4 MHz ¹³C NMR spectra of a series of para‐substituted chlorobenzenes. The high‐field isotope shift effect ¹Δ¹³C(³⁷Cl) was established from the relationship between the chlorine isotopomeric ratio and the carbon peak intensities. It was found that the ¹Δ¹³C(³⁷Cl) values are in the range of −4.0 to −5.2 ppb. The isotope shifts tend to decrease as the electron‐attracting character of the substituent increases, providing a linear correlation between the isotope shift and the chemical shift of the chlorine‐bearing carbon.