Synthesis of a π-Conjugated Polymer via Palladium-Catalyzed Direct Arylation Polycondensation of 3,4-Ethylenedioxythiophene with Dibromofluorene: Effect of Different Microwave Heating Systems on the Polycondensation

Abstract

Palladium-catalyzed direct C-H arylation polycondensation of 3,4-ethylenedioxythiophene with2,7-dibromo-9,9-dioctylfluorene was carried out under oil bath heating and microwave heating conditions. The polycondensation [Conditions: Pd(OAc)₂ , PivOH, K₂CO₃, DMAc (0.3 M), 1 h] at various temperatures (80-120 o C) gave analternating copolymer, poly(3,4-ethylene-dioxythiophene-alt-9,9-dioctylfluorene-2,7-diyl). Although the microwave heating was effective for the polymer synthesis, we found that the polymerization efficiency depended on the apparatus used. Namely,the molecular weights (the values of M_w and M_n) of resulting polymer from 3,4-ethylenedioxythiophene and2,7-dibromo-9,9-dioctylfluorene were different when the polycondensation was performed at 80-120 o C by CEM (Discover) or Anton Paar (Monowave).