Implementation of Sustainable Solvents in Green Polymerization Approaches. Issue 2 (15th December 2020)

• Record Type: Journal Article
• Authors: Conelli, Daniele; Margiotta, Nicola; Grisorio, Roberto; Suranna, Gian Paolo
• Is Part Of: Macromolecular chemistry and physics. Volume 222:Issue 2(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-15
• Subjects: anisole -- direct arylation polymerization (DArP) -- propylene carbonate -- regioregularity -- sustainable solvents -- tandem Suzuki–Heck polymerization; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.202000382
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract: In modern polymer chemistry directed toward the synthesis of conjugated materials, the synthetic routes devised to achieve the process sustainability are based on CH bond activation. This prerequisite distinguishes both the tandem Suzuki−Heck as well as the direct arylation polymerizations (DArP); however, their compatibility with environmentally benign solvents still represents a challenge. In this paper, the implementation of sustainable solvents for the synthesis of poly(9, 9‐dioctylfluorenylene‐vinylene) by using the traditional Pd(AcO)2 /P( o ‐Tol)3 /NEt3 catalytic system is described. It is assessed that selected green solvents (i.e., anisole and propylene carbonate) constitute the ideal media for the tandem Suzuki–Heck polymerization. Furthermore, by modulating medium polarity using mixtures of these green solvents and changing the reaction temperature, a suitable compromise between high molecular weights and regioregularity of the resulting polymers is reached. Conversely, the presence of propylene carbonate is deleterious for the DArP of 2‐bromo‐3‐hexylthiophene, while it is found that catalyst performances in anisole strictly depend on the palladium source used. The best conditions are obtained using PdCl2 (PPh3 )2 as the precatalyst, affording a highly regioregular (93%) poly(3‐hexylthiophene) in quantitative yields and high molecular weights (26.7 kg mol −1 ). Abstract : The sustainability of the polymerization protocols requires the optimization of the reaction conditions in alternative green solvents. Molecular weights and regioregularity of poly(fluorenylene‐vinylene) and poly(3‐hexylthiophene) can be improved by modulating temperature, medium polarity, and precatalyst in the case of anisole and propylene carbonate as the solvent.