Planar para‐phenylene oligomers

Planar, methylene‐bridged quinque‐ and septiphenyl oligomers were synthesized as soluble, hitherto unknown compounds. The series of homologous and planar ladder‐type oligophenyls (ter‐, quinque‐, septiphenyl) was characterized especially with respect to their optical properties (absorption and emission) as function of increasing chain length, and compared to the corresponding ladder‐type polyphenylene. An effective conjugation length of about 12 benzene rings was determined within this series of planar oligo‐ and polyphenylenes.