The Albatrossenes: Large, Cleft-Containing, Polyphenyl Polycyclic Aromatic Hydrocarbons

The syntheses and X-ray structures of very large
polycyclic aromatic compounds containing clefts defined
by polyphenylaryl groups are described. The
C2-symmetric “albatrossenes”
1,3-bis(heptaphenyl-2-naphthyl)benzene
(7a) and 1,3-bis(heptaphenyl-1-naphthyl)benzene
(12a), as well as brominated derivatives, were synthesized
by the
addition of tetraphenylbenzyne to the appropriate polyphenyl
biscyclopentadienones. The 2-naphthyl isomers have
wide, shallow clefts, and the 1-naphthyl isomers have deep, narrow
clefts which were observed to change size
dramatically in different crystal environments. In a similar way,
1,3,5-tris(pentaphenylphenyl)benzene (19), a
D3-symmetric molecular propeller with a diameter of 21 Å, and
1,3,5-tris(heptaphenyl-2-naphthyl)benzene (22)
were
prepared by the addition of diphenylacetylene and tetraphenylbenzyne,
respectively, to a triscyclopentadienone.