The molecular structure of cyclopentene in solution as obtained from a nematic phase proton N.M.R. study

Abstract

The novel technique of automated spectral analysis proposed in recent papers has been applied to the proton N.M.R. spectrum of cyclopentene partially oriented in a nematic solvent. The dipolar coupling constants thus extracted are used to obtain information about the structure of the molecule in solution and about the dynamic details of its large amplitude vibration. It is concluded that cyclopentene exists in an equilibrium conformation characterized by a puckering angle of 30·8°. The data favour a model in which the large amplitude internal motion and the overall reorientation of the molecule are correlated, thus requiring an infinite number of orientation tensors.