Chemical Shifts and Temperature Dependence of Spin—Spin Coupling Constants of Fluoropropenes

摘要: NMR spectral parameters of the compounds CF2=CFY in which Y is CF3, CF2Cl, CF2Br, CF2I, or COF have been measured at room temperature and spin—spin coupling constants four these molecules investigated range from —100° to + 100°C. Some aspects dependence can be related changing equilibria between cis—trans rotational isomers, but there an intrinsic dependence, aside effects, attributed excitation molecular vibrations. Particular J values change magnitude one direction with increasing are found opposite regular fashion as goes through series halogen‐substituted fluorine iodine. Chemical shifts observed discussed terms effects substituents.