Molecular structure of p-nitrobiphenyl. A comparison of the results of X-ray crystal analysis with semi-empirical calculations of conformation

Abstract

The crystal and molecular structure of p-nitrobiphenyl has been determined from photographic X-ray data. Crystals are orthorhombic, space group Pbca, with Z= 8, in a unit cell of dimensions a= 23·210, b= 11·370, and c= 7·568 Å. The crystal structure was solved by direct methods and has been refined by least-squares methods to R 0·067 for 1495 visually estimated reflections. The value of the dihedral angle between phenyl rings is 33°. Conformational analysis was carried on by the semi-empirical method both for the isolated molecule and for the molecule in the crystal; results were in fair agreement with those found experimentally.