Structure of a 2-arylquinoline dimer, a compound with a new ring system

The title compound, 6,15-dimethyltribenzo-[c,f,j]naphtho[1,2,3,4-lmn][2,7]phe nanthroline was obtained in low yield from the reaction of 2-(4-methylphenyl)quinoline and various aryllithiums. The compound is a 'dimer' in which two phenylquinoline units are joined by three bonds; the dimer has exact twofold symmetry. Non-bonded interactions produce substantial out-of-plane distortions. Bond lengths between the two phenylquinoline halves suggest that the two phenylquinoline pi-electron systems are more-or-less undisturbed and linked by single bonds. Molecular-mechanics optimizations of models with inversion (1) and twofold symmetry suggest that the latter conformation is the more stable of the two to a slight extent.