Synthesis and properties of novel heat-resistant fluorescent conjugated polymers with bisindolylmaleimide

Conjugated polymers with bisindolylmaleimide (BIM) backbone are obtained by the condensation polymerization of methyl and octanyl N-substituted BIMs with 4,4'-difluoro-diphenylsulfone and 4,4'-difluoro-diphenylketone. The structures of polymers are confirmed by FTIR and NMR spectroscopy. The polymers exhibit both high glass transition temperatures (T_g > 175 °C) and high decomposition temperatures (T₅ > 395 °C). Meanwhile, The UV–vis absorption and fluorescence spectra of the polymers are similar to the corresponding substituted BIMs. The quantum chemistry calculations indicate that the first excited states of polymers are mostly contributed by BIM structures.