Poly(arylene vinylene) Synthesis via a Precursor Step-Growth Polymerization Route Involving the Ramberg–Bäcklund Reaction as a Key Post-Chemical Modification Step

• Published in: Macromolecules Vol. 51; no. 15; pp. 5852 - 5862
• Main Authors: Aravindu, Kunche, Cloutet, Eric, Brochon, Cyril, Hadziioannou, Georges, Vignolle, Joan, Robert, Frédéric, Taton, Daniel, Landais, Yannick
• Format: Journal Article
• Language: English
• Published: American Chemical Society 14.08.2018
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/acs.macromol.8b00676

The synthesis of conjugated copolymers based on poly­(fluorene vinylene) [PFV] and poly­(fluorene vinylene-co-carbazole vinylene) [PFVCV] was achieved via a previously unexplored precursor three-step synthetic route involving the Ramberg–Bäcklund reaction. The resulting π-conjugated (co)­polymers proved highly soluble in common organic solvents, such as DCM, THF, or CHCl3. The solution step-growth polymerization between 2,7-bis­(bromomethyl)-9,9′-dihexyl-9H-fluorene [F-Br] and 2,7-bis­(mercaptomethyl)-9,9′-dihexyl-9H-fluorene [F-SH] was carried out under basic conditions at 100 °C in a mixture of MeOH and THF. The resulting polysulfides were then subjected to an oxidation reaction using m-CPBA, which was followed by the Ramberg–Bäcklund reaction in the presence of CF2Br2/Al2O3–KOH, thus achieving the desired PFV. Similarly, PFVCV could be synthesized through the same three-step sequence employing, in this case, 2,7-bis­(mercaptomethyl)-9-(tridecan-7-yl)-9H-carbazole (C-SH) and F-Br. Conjugated polymers with apparent molecular weights up to 15 kg mol–1 and exhibiting promising optical features were obtained following this convenient synthetic strategy.