Nuclear magnetic resonance spectra of oriented 4-spin systems with C2v symmetry (AA′BB′). The spectrum of thiophene

The general Hamiltonian for the nuclear magnetic resonance (n.m.r.) spectra of oriented 4-spin systems with C2v symmetry of the type (AA′BB′) is reported. The system can be discussed analytically, if only the direct coupling between the various nuclei is considered. The expressions for transition frequencies and intensities for such a case are given.The proton spectrum of thiophene in the nematic phase of p,p′-di-n-hexyloxyazoxybenzene has been analyzed. The ratios of the various interproton distances are determined.