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

Publisher Website
Google Scholar
Abstract
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 in four of these molecules have been investigated in the range of temperature from —100° to + 100°C. Some aspects of the temperature dependence of the coupling constants can be related to changing equilibria between cis—trans or rotational isomers, but there is an intrinsic temperature dependence, aside from these effects, which is attributed to excitation of molecular vibrations. Particular J values which change magnitude in one direction with increasing temperature are found to change magnitude in the opposite direction in regular fashion as one goes through the series of halogen‐substituted compounds from fluorine to iodine. Chemical shifts observed at room temperature are discussed in terms of the effects of substituents.

This publication has 17 references indexed in Scilit: