New Strategy for Synthesis of Polyphenylene Substituted Dendronized Monomers Containing Fluorene Unit and the Study of Their Properties

A mild and efficient synthetic strategy has been developed for the synthesis of polyphenylene substituted dendronized monomers containing fluorene unit, namely 2,7-dibromo-9,9-di(4-(pentaphenylphenyl)benzyl) fluorene 5a and 2,7-dibromo-9,9-di(4-(2,3,4,5-tetraphenylphenyl)benzyl) fluorene 5b. The present synthetic route was found efficient, which avoids the unwanted by-product formation and has fewer column chromatography purification requirements. The synthesized compounds 5a and 5b showed promising optical properties. Moreover, TGA study revealed good thermal stability of the synthesized compounds.