Isoindigo-Based Donor-Acceptor Conjugated Polymers

The synthesis of the first set of isoindigo-based donor-acceptor conjugated polymers and their optical and electrochemical properties was reported. Six representative isoindigo-based conjugated polymers were synthesized by the palladium-catalyzed polycondensations of 6,60-dibromoisoindigo compound with functionalized electron-rich moieties. The synthesis was carried out in two high yielding steps from the commercially available 6-bromooxindole and 6-bromoisatin. The polycondensations were carried out under Stille or Suzuki coupling conditions depending on the nature of the electron-rich comonomer, using Pd2(dba)3 as a catalyst and P(o-tyl)3 as the corresponding ligand. The proton NMR spectra of all polymers show broad peaks in the 6.5-9.4 ppm range corresponding to the aromatic protons, as well as broad multiplets in the 0.70-1.80 ppm corresponding to the alkyl chain protons other than the ones on the tertiary carbon of the branched chains.