Nematic phase nuclear magnetic resonance studies of some disubstituted pyridines. Molecular geometry of 2,6-difluoropyridine

Abstract

The n.m.r. spectra of 2,6-difluoropyridine, 2,6-dichloropyridine and 3,5-dichloropyridine oriented in a nematic phase have been analysed and the average orientations of these molecules discussed and compared with other pyridines. The geometry of 2,6-difluoropyridine has been derived and indicates ring distortion in the vicinity of the fluorine substituents. Absolute signs of the major indirect coupling constants have been deduced.