Fluoride-promoted carbonylation polymerization: a facile step-growth technique to polycarbonates

• Published in: Chemical science (Cambridge) Vol. 8; no. 7; pp. 4853 - 4857
• Main Authors: Olsson, J. V., Hult, D., Garcia-Gallego, S., Malkoch, M.
• Format: Journal Article
• Language: English
• Published: CAMBRIDGE Royal Soc Chemistry 01.07.2017
• Subjects: Activating reagents; Building blockes; Byproducts; Carbonylation; Carbonyldiimidazole; Catalysts; Catalytic polymerization; Chemistry; Chemistry, Multidisciplinary; Diols; Efficient catalysts; Fluorine compounds; Glass transition; Growth techniques; Methodology; Monomers; Physical Sciences; Polycarbonates; Polymerization; Proof of concept; Science & Technology; Step-growth polymerizations; Synthesis (chemistry); ONE-POT; CO2; ESTERS; CHEMISTRY; RING-OPENING POLYMERIZATION; CYCLIC CARBONATES; ALIPHATIC POLYURETHANE DENDRIMERS; CONVERGENT SYNTHESIS; TOOL
• ISSN: 2041-6520; 2041-6539; 2041-6539
• DOI: 10.1039/c6sc05582f

Fluoride-Promoted Carbonylation (FPC) polymerization is herein presented as a novel catalytic polymerization methodology that complements ROP and unlocks a greater synthetic window to advanced polycarbonates. The overall two-step strategy is facile, robust and capitalizes on the synthesis and step-growth polymerization of bis-carbonylimidazolide and diol monomers of 1,3-or higher configurations. Cesium fluoride (CsF) is identified as an efficient catalyst and the bis-carbonylimidazolide monomers are synthesized as bench-stable white solids, easily obtained on 50-100 g scales from their parent diols using cheap commercial 1,1'-carbonyldiimidazole (CDI) as activating reagent. The FPC polymerization works well in both solution and bulk, does not require any stoichiometric additives or complex settings and produces only imidazole as a relatively low-toxicity by-product. As a proof-of-concept using only four diol building-blocks, FPC methodology enabled the synthesis of a unique library of polycarbonates covering (i) rigid, flexible and reactive PC backbones, (ii) molecular weights 5-20 kg mol(-1), (iii) dispersities of 1.3-2.9 and (iv) a wide span of glass transition temperatures, from -45 up to 169 degrees C.