Organocatalytic controlled anionic ring-opening polymerization of carbazole-containing thiiranes

Abstract

The anionic ring-opening polymerization of carbazole-containing monomers, (9-carbazolylmethyl)thiirane (M1)and (3,6-di-tert-butyl-9-carbazolylmethyl)thiirane (M2), with hexanethiol or pentaerythritol tetrakis(3-mercaptopropionate)(PETMP)as initiators and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)as catalyst at 20 °C in tetrahydrofuran or N,N-dimethylformamide as solvents has been studied. The polymerization of these monomers proceeds in a living fashion affording linear and star-shaped polymers with controlled molecular weight (Mn = 4000–15,000 g mol−1)and relatively low polydispersity (Đ < 1.3). It was demonstrated that end-capping of polymers by trifluoroacetic anhydride allowed to protect thiol end groups from oxidative coupling, which typically leads to the broadening of molecular weight distribution of the synthesized polymers. The thermal, photophysical and electrochemical properties of the synthesized linear and star-shaped polymers were estimated.