Maghnite‐H+ Catalytic Synthesis and Characterization of Polyindenes and Oxidized Derivatives

Abstract

This work presents a comprehensive study on the physico‐chemical and electrochemical properties of polyindenes (PIns) synthesized by Maghnite‐H+‐catalysed polymerization of indene (benzocyclopentadiene) in CH2Cl2 at different temperatures, and their oxidative derivatives by subsequent treatment with FeCl3. The polymers are characterized by TG, FT‐IR, XPS and UV‐vis spectroscopies, as well as electrical conductivity and voltammetric measurements, analysing the influence of synthesis temperature and post‐oxidation. Results show that the PIns synthesized at different temperatures present quite similar thermogravimetric behavior and UV spectra. Nevertheless, FTIR and XPS reveal significant differences in chemical composition and polymer structure depending on this temperature. At higher temperatures, indenyl coupling proceeds via 1,2 carbon atoms to obtain more compact and less defective PIns with higher yields. At lower temperatures, polymerization through 1,3 carbon atoms may also occur, leading to polymers with a larger number of defects and oxygen functionalities and lower yields. FeCl3 treatment causes the introduction of some oxygen functionalities in the compact PIn60 and PIn80 polymers, without significantly affecting their molecular structure and electrical conductivity. Finally, cyclic voltammetry demonstrates that, despite not electro‐active, these partially oxidized PIns show enough electrical conductivity for different applications.