Ring-Opening Polymerization with Zn(C₆F₅)₂-Based Lewis Pairs: Original and Efficient Approach to Cyclic Polyesters

Abstract

Dual systems combining Zn(C6F5)2 with an organic base (an amine or a phosphine) promote the controlled ring-opening polymerization of lactide and ε-caprolactone. The Lewis pairs cooperate to activate the monomers, affording well-defined high molecular weight cyclic polyesters. Efficient chain-extension gives access to cyclic block copolymers.

Zinc calixarene complexes for the ring opening polymerization of cyclic esters

“…30 Disappointingly, the pre-polymerization screening of compound 1 indicated no reaction between the benzyl alcohol (BnOH) and the Zn-C 6 F 5 moiety, which was also the conclusion obtained by Schnee et al and Piedra-Arroni et al when Zn(C 6 F 5 ) 2 ·toluene was employed in the presence of either BnOH or amine/phosphine 35 respectively. 13,14 In such systems, the catalyst was thought to behave as a 'monomer activator' rather than proceeding via a 'coordination insertion' pathway; the lack of activity contrasts with a …”

“…13,14 To ensure that the polymerization would proceed through a 'coordination insertion' mechanism, the pentafluorophenyl moiety was substituted for a more nucleophilic group. To isolate a zinc alkoxide, firstly the methyl zinc derivative (compound 2) was synthesized following the literature 15 procedure.…”

Computational Studies on the Selective Polymerization of Lactide Catalyzed by Bifunctional Yttrium NHC Catalyst

“…To exploit the potential of NHC-ZnR2 complexes, different approaches have been followed in which the synthesis and characterization of NHC-ZnR2 are carried out, and these complexes have then been used in ROP [33]. Controlled ROP of lactide was carried out by a dual system Zn(C 6 F 5 ) 2 combined with an amine or phosphine as organic bases [34]. In this context, Bourissou and co-workers reported a dual catalytic system combining an original cationic zinc complex with a tertiary amine, which was shown to promote efficiently and in a controlled manner the ROP of lactide under mild conditions [31].…”

Multimetallic Lithium Complexes Derived from the Acids Ph2C(X)CO2H (X=OH, NH2): Synthesis, Structure and Ring Opening Polymerization of Lactides and Lactones

“…4.3 ppm suggests the absence of cyclic PLA. [12] The MALDI-TOF spectrum of the PVL (run 7, table 3, figure S26, SI) revealed a family of peaks separated by 100 Da (the molecular weight of the monomer), consistent with the presence of only oligomeric PVL. A kinetic study using 1 and 3 -5 ( figure 12) at 110 o C revealed that the polymerization rate of the ROP of δ-valerolactone exhibited a first order dependence on the δ-valerolactone concentration ( figure 12, left).…”