Multiple quantum nuclear magnetic resonance spectra of partially oriented styrene in a nematic phase

Proton multiple-quantum nuclear magnetic resonance (MQNMR) spectra of styrene partially oriented in a nematic liquid crystal were acquired using the magnetic field gradient method. Six-, seven- and eight-quantum spectra were iteratively solved to yield all intramolecular dipolar couplings (D_ij) which were used to determine the molecular shape of styrene. The dipolar couplings were fitted to a model averaging between four equivalent non-planar conformations of the molecule. Ignoring vibrational corrections, the analysis was consistent with a non-planar molecular geometry with a dihedral angle of approximately 16 degrees between the olefinic fragment and the aromatic ring.