Abstract: | The 13C? 13C spin–spin coupling constants in natural abundance oxetane, thietane, cyclobutanone, bromo-and chlorocyclobutane have been measured. Furthermore, the 13C isotope-induced changes in the chemical shifts of the different 13C nuclei in the molecules mentioned above are reported. These shifts are normally to higher magnetic field; in cyclobutanone, however, the resonance of the carbonyl carbon has shifted to lower field because of the substitution of 13C?3 for 12C?3. |