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]phenanthroline, 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 phe nylquinoline halves suggest that the two phenylquinoline pi-electron s ystems are more-or-less undisturbed and linked by single bonds. Molecu lar-mechanics optimizations of models with inversion (1BAR) and twofol d symmetry suggest that the latter conformation is the more stable of the two to a slight extent.