Selective bromination of 2,5-bis(2-thienyl)pyrroles and solid-state polymerization through the β-carbon of pyrrole

Abstract

Bromination of 2,5-bis(2-thienyl)pyrrole with NBS in AcOH–THF prefers the β-position of pyrrole over the α-position of thiophene. A DFT study and experiments in different solvent systems suggest the important role of the solvent in tuning the selectivity. Unusual solid-state polymerization (SSP) of β,β′-dibrominated 2,5-bis(2-thienyl)pyrrole was observed through the β-C of pyrrole to afford the bromine doped conjugated polymer. DSC, CHN and SEM analyses were carried out to study the SSP process.