Nuclear magnetic resonance spectra of polyfluorobuta-1,3-dienes. Part I. Hexafluorobuta-1,3-diene: temperature-dependent coupling constants

Abstract

The six-spin system of hexafluorobuta-1,3-diene has been analysed and values and signs of all the coupling constants have been thereby obtained, and assigned. At 34°, the following values have been obtained: J_AA′ 4·9, J_MM′ 11·2, J_XX′–30·0, J_AM 52·4, J_AM′ 2·4, J_AX 32·4, J_AX′ 2·5, J_MX–118·8, J_MX′ 14·3 Hz, where A, M, and X refer to the trans-1,4-, cis-1,4-, and 2,3-fluorines, respectively. All coupling constants except J_AM′, J_AX′, and J_MX′ show appreciable variation with temperature.