Effect of Solvents on 19F Spin—Spin Coupling Constants

Abstract

The effects of solvents on the coupling constants of the compounds CF 2 = CFBr , CF 3 CFCl 2 , and CF 2 BrCFBrCl have been studied. The coupling constants are found to vary with the solvents. This implies that intermolecular interactions affect coupling constants to a degree that is not negligible. The variations in the coupling constants are to some extent correlated with the size, electronic character, and dipolar nature of the solvent molecules. The temperature dependence of fluorine coupling constants that has been reported previously may be due to this temperature‐dependent molecular interaction as well as the population of excited vibrational states.