Multiple-quantum 1 H NMR spectroscopy was used to simplify
In this paper, we present a study of oriented biphenyl. The the analysis of the complicated one-quantum spectrum of the 10molecular structure of biphenyl is shown in Fig. 1. The biphenyl spin molecule biphenyl dissolved in a nematic solvent. An eightmolecule is a 10-spin system, and the one-quantum spectrum quantum spectrum was analyzed to obtain estimates of all dipolar of biphenyl, shown in Fig. 2, is very complicated despite the coupling constants and chemical shifts, which were used as a starthigh degree of molecular symmetry. Biphenyl has attracted ing point to solve the one-quantum spectrum. The dipolar coumuch interest among researchers because of the low barrier to plings from the one-quantum spectrum were used, in combination rotation about the interring C-C bond. The potential associated with those determined in a previous study using different liquid-
with the interring C-C rotation has a minimum at the equilibcrystal solvents, to obtain vibrationally corrected geometrical parameters and orientational order parameters. The effective inter-rium dihedral angle, u min . Conjugation between the p orbitals nal rotational potential was found to be shifted slightly toward a in different phenyl rings favors planarity. However, interring more planar configuration relative to the gas-phase potential, with steric repulsion between H atoms causes a repulsion that favors an equilibrium dihedral angle of 37ะ.