Molecular compounds and complexes. XI. The crystal structure of the π-molecular compound phenanthrene-2,3-dichloro-5,6-dicyano-p-benzoquinone

Abstract

We have studied the crystal structure of the n-molecular compound phenanthrene-2,3-dichloro-5,6-dicyanop-benzoquinone (PH-DDQ) to compare the component arrangement in the mixed stacks with that found in benzo [clphenanthrene-DDQ [Bernstein, Regev & Herbstein, Acta Cryst. (1977), B33, 1716-17241. PH-DDQ is orthorhombic, a = 16.101 (2), b = 7.244 (3), c = 15.544 (3) ,/k, space group Pca2~, Z = 4. The structure was solved by direct methods and refined to R = 0.056 using 1632 unique reflections. The structure is of the well known mixed-stack type, with the stack axis along b. The crystal structures of PH-DDQ and BPH-DDQ are quite different in the mutual arrangement of the components. Dimensions of the component molecules do not differ significantly from those obtained in other analyses but appear to be the most accurate currently available. Both component molecules are slightly but significantly non-planar, presumably due to packing effects.

Electrostatic potential mapping of polycyclic aromatic hydrocarbon diol epoxides using a dipole

“…The benzene diol epoxide geometry was optimized using the molecular mechanics (MM2) method [20], and then the experimentally determined geometries of the remaining parts (rings) of the molecules were fused [21,22] together. The bond lengths and bond angles at the site of fusion were optimized using the MNW method.…”