Crystal structure of the doubly bridged biphenyl, 2-chloro-4,5,9,10-tetrahydropyrene

Abstract

The title compound (I) crystallizes in space group P2₁/c with a= 8·509 ± 0·001, b= 8·094 ± 0·002, c= 26·031 ± 0·003 Å, β= 92·38 ± 0·09° and Z= 6. The structure was solved from X-ray diffraction data by Patterson and Fourier methods and refined by block-diagonal least-squares techniques to R 0·086 for 1252 observed reflections measured on a diffractometer. The analysis shows two crystallographically distinct molecules of different conformation, one of which is disordered. These configurations are associated with different orientations of the ethylene bridges. In one molecule the angle between the planes of the two benzene rings is 16·9°, whereas in the other it is close to zero.