Synthesis of Conjugated Polymers by Sustainable Suzuki Polycondensation in Water and under Aerobic Conditions

Abstract

Conjugated semiconducting polymers are key materials enabling plastic (opto)electronic devices. Research in the field has a generally strong focus on the constant improvement of backbone structure and the resulting properties. Comparatively fewer studies are devoted to improving the sustainability of the synthetic route that leads to a material under scrutiny. Exemplified by the two established and commercially available luminescent polymers poly(9,9-dioctylfluorene-alt-bithiophene) (PF8T2) and poly(9,9-dioctylfluorene-alt-benzothiadiazole) (PF8BT), this work describes the first examples of efficient Suzuki-Miyaura polycondensations in water, under ambient environment, with minimal amount of organic solvent and with moderate heating. The synthetic approach enables a reduction of the E-factor (mass of organic waste/mass of product) by 1 order of magnitude, without negatively affecting molecular weight, dispersity, chemical structure, or photochemical stability of PF8T2 or PF8BT.

Green Synthesis of Lactone‐Based Conjugated Polymers for n‐Type Organic Electrochemical Transistors

“…[ 29,35 ] To address these critical issues, future materials design should integrate monomers enabling both high performance and synthesis via environmentally friendly and economic polymerization routes (e.g., aldol polycondensation). [ 33 ]…”

“…In a parallel trend, the need for greener and bio-friendly materials is pushing researchers to think beyond standard synthesis methods and integrate polymerization strategies free from highly toxic reagents, such as the hazardous monomers and transition-metal catalysts used in Stille and Suzuki couplings. [32,33] Alternative synthesis pathways would enable both sustainable products manufacturing and meet the strict regulations concerning the use of chemicals in biomedical devices. [33,34] To date, most semiconducting polymers for OECTs are synthesized via transition-metal-mediated cross-coupling polymerizations, producing stoichiometric quantities of hazardous byproducts containing heavy metals, such as organostannane.…”

“…[32,33] Alternative synthesis pathways would enable both sustainable products manufacturing and meet the strict regulations concerning the use of chemicals in biomedical devices. [33,34] To date, most semiconducting polymers for OECTs are synthesized via transition-metal-mediated cross-coupling polymerizations, producing stoichiometric quantities of hazardous byproducts containing heavy metals, such as organostannane. [29,35] To address these critical issues, future materials design should integrate monomers enabling both high performance and synthesis via environmentally friendly and economic polymerization routes (e.g., aldol polycondensation).…”

A Donor Polymer with a Good Compromise between Efficiency and Sustainability for Organic Solar Cells

“…We have calculated (see SI) the E factor for the BDT monomer bearing long alkyl chains and used for the synthesis of PBDT3T , using a recent protocol which takes into account the recyclability of the reaction solvents. [ 27 ] Following this procedure, an even more pronounced reduction of the E factor could be detected when compared with the literature BDT analogue (220 vs 5800), reinforcing the sustainability of the MCR approach in the production of organic materials for OPV. The calculated E factor for the synthesis of the BDT monomer is in the same order as the one of the commercially available 3T monomer.…”

First demonstration of the use of open-shell derivatives as organic luminophores for transparent luminescent solar concentrators

“…[38][39][40][41][42] Some of us already demonstrated the validity of the approach in the preparation of polyconjugated materials. [43][44][45] PyBTM-H is a particularly challenging substrate for the S-M coupling in terms of reactivity and selectivity. Chlorine generally requires relatively harsh reaction conditions (high temperature, expensive and/or custom-made phosphines) and, aside from steric hindrance, all the 8 chlorine atoms of the molecule are, at least in principle, reactive.…”