CRYSTAL AND MOLECULAR-STRUCTURE OF PERYLENE-2,5-DIBROMO-3,6-DICHLORO-PARA-BENZOQUINONE COMPLEX

Crystals of the 1: 1 molecular complex of perylene-2,5-dibromo-3,6-dichloro-p-benzoquinone are triclinic, with a = 8.669, b = 9.697, c=7.321 Å, α= 103.20, β=110.92, γ=64.60°, space group P1, Z=l. The structure has been determined from diffractometer data by the heavy atom method and refined using the full-matrix least-squares method to R 0.069 for 2241 independent reflections. Stacks, with alternating donor and acceptor molecules, extend along the c direction. The acceptor molecule assumes two orientations, with a population ratio 1:1. A small degree of correlative change in the C-C bond lengths has been found in the perylene molecule on complex formation. The geometry of the quinonoid skeleton of the acceptor is similar to those of the anils and their complexes.