NMR Spectra of Bicyclic Compounds Oriented in the Nematic Phase. Part 1. The Spectrum of Quinoxaline

Abstract

The possibility of the determination of the structure of molecules oriented in the nematic phase of liquid crystals for relatively large aromatic bicyclic compounds is studied. The spectrum of quinoxaline is investigated in the nematic phase of 4-methoxy benzylidene, 4-amino-α-methyl cinnamic acid-npropyl ester. The shape of the proton skeleton is iteratively determined. Values of some of the indirect spin spin coupling constants are determined. The molecule is shown to orient preferentially with its plane and the C₂, axis along the direction of the magnetic field.