Polyhedral oligomeric silsesquioxanes appended conjugated soluble polymers based on thieno[3,4-c]pyrrole-4,6‑dione acceptor unit
By Çakal, Deniz; Cihaner, Atilla; Önal, Ahmet M.
Published in Electrochimica Acta
2021
Abstract
A series of new donor-acceptor-donor type fluorescent molecules incorporating thieno[3,4-c]pyrrole-4,6‑dione (TPD) as the acceptor unit were synthesized. TPD acceptor unit was modified with polyhedral oligomeric silsesquioxanes (POSS) cages and integrated with thiophene and alkylenedioxythiophene derivatives (3,4-ethylenedioxythiophene (EDOT) and 3,4-propylenedioxythiophene (ProDOT)) using Stille coupling reaction. The monomers, T2-POSS, E2-POSS, and P2-POSS, were polymerized successfully via electrochemical and chemical polymerization techniques. As a fingerprint of d-A-D monomers, all monomers showed dual band characteristics due to intramolecular charge transfer. Soluble polymers exhibited reversible electrochromic responses electrochemically and chemically with fast switching times and high coloration efficiencies. E2-POSS and its polymer PE2-POSS exhibited the lowest oxidation potential and band gap values as compared to their thiophene and ProDOT analogs. Also, P2-POSS and its chemically obtained fluorescent polymer PP2-POSS-C represented high sensitivity towards Fe2+ and Fe3+ ions, which makes them potential candidates to be amenable for use in ion sensing.