Synthesis of hyperbranched polymers with precise conjugation length

A set of AB(2) type monodisperse conjugated oligomers carrying two bromo functional groups and one boronic ester functional group were prepared by iterative deprotection and Sonogashira cross-coupling reactions. Suzuki polycondensation of these AB(2) type monodisperse oligomers afforded hyperbranched polymers. The hyperbranched conjugated polymers we prepared possess not only precisely controlled conjugation length like monodisperse conjugated oligomers but also the structural feature of hyperbranched polymers. Optical property investigation demonstrated that the maximum absorption and emission wavelength red-shifted along with the increasing of the conjugation length between the two branching points and the hyperbranched structure could effectively reduce the aggregation of the conjugated polymer chains. (c) 2006 Wiley Periodicals, Inc.