Crystal structure of the 1 : 1 molecular complex of chrysene and 7,7,8,8-tetracyanoquinodimethane

Abstract

The crystal and molecular structure of the title complex has been determined by three-dimensional X-ray diffraction methods. Crystals are triclinic, a= 7·255, b= 7·995, c= 9·210 Å, α= 99·8, β= 89·7, γ= 92·9°, space group P, Z= 1. The structure was determined from 1288 diffractometer data by Patterson and Fourier methods and refined by least-squares methods to R 0·104. In the crystal, alternate chrysene and tetracyanoquinodimethane molecules form stacks along the a axis. The mean separation of the molecular planes is 3·37 Å and the interplanar angle is 3·4°. The interplanar separations in a series of related tetracyanoquinodimethane complexes are shown to be dependent on crystal system as well as orbital energies. The relative orientation of the two molecules is not ideal for maximum overlap of highest-filled-donor and lowest-vacant-acceptor orbitals, and suggests that dipoldipole interactions and interactions involving other donor and acceptor orbitals are also important in determining orientation. The dimensions of both molecules are in good agreement with known values, and no disorder is apparent.