PLANAR PARA-PHENYLENE OLIGOMERS

Planar, methylene-bridged quinque- and septiphenyl oligomers were synt hesized as soluble, hitherto unknown compounds. The series of homologo us and planar ladder-type oligophenyls (ter-, quinque-, septiphenyl) w as characterized especially with respect to their optical properties ( absorption and emission) as function of increasing chain length, and c ompared to the corresponding ladder-type polyphenylene. An effective c onjugation length of about 12 benzene rings was determined within this series of planar oligo- and polyphenylenes.