Chain end-group selectivity using an organometallic Al(iii)/K(i) ring-opening copolymerization catalyst delivers high molar mass, monodisperse polyesters

Abstract

A heterodinuclear Al(iii)/K(i) organometallic ring-opening copolymerization catalyst shows exceptional rates, end-group selectivity and good loading tolerance to deliver monodisperse polyesters with molar masses up to 91 kg mol−1.

A highly active, thermally robust iron(iii)/potassium(i) heterodinuclear catalyst for bio-derived epoxide/anhydride ring-opening copolymerizations

“…[51][52][53] In order to target high molar mass polyesters, an organometallic derivative of the Fe(III)/K(I) catalyst should also be targeted. 29…”

“…28 An Al( iii )/K( i ) organometallic catalyst yielded high molar mass polyesters (>90 kg mol −1 ) with promise as engineering thermoplastics. 29 Here, an Fe( iii )/K( i ) complex, coordinated by the same ancillary ligand, is targeted (Fig. 1); the metal combination is selected based on catalytic precedent, elemental abundance, toxicity and cost.…”

Ring Opening Copolymerization of Boron-Containing Anhydride with Epoxides as a Controlled Platform to Functional Polyesters

“…Another opportunity is to couple it with CO 2 /epoxide ROCOP and/or cyclic ester/carbonate ROP, using switchable catalysis, to produce block sequence selective copolymers. 49,50 Using these switchable methologies, epoxide/anhydride ROCOP blocks were combined with other polymers to furnish thermoplastics, 51,52 elastomers, 53,54 pressure sensitive adhesives, 55 hydrolysable surfactants, and amphiphile nanoparticles, 56 and additives to toughen bio-based plastics like PLA. 57 We reasoned that the significant co-monomer diversity accessible in epoxide/anhydride ROCOP might allow access to various boron-polyesters and offer a route to broaden their available functionalities and properties.…”

“…Polymerizations were conducted using 1:4:100:400 loadings of [ The AlK catalyst is among the fastest catalysts reported for CHO/PA ROCOP and hence was tested under more demanding conditions (Table 1, # 2). 52 These conditions include lower catalyst loading (400 equiv or 0.25 mol % vs anhydride), higher epoxide loading (2000 equiv), and higher temperature (100 °C). The polymerization proceeded to complete anhydride consumption within 1.5 h, resulting in a turnover-frequency (TOF) of 267 h −1 .…”

From CO2 to CS2: Mechanistic mapping of cooperative (CS2/CO2)/epoxide ring-opening copolymerisation catalysis

“…[41,42] These catalysts are often synthetically very accessible and in particular Williams and coworkers presented a series of well-performing catalysts based on vanillin derived ligands (alike H2L Figure 2) for all-oxygen ROCOP. [43][44][45][46] Furthermore, heterobimetallic catalysts in general maintain activity at low CO2 pressure as well as high dilution, the latter being attractive for CS2/epoxide ROCOP requiring an excess of liquid CS2. However, it is unclear whether heterobimetallic cooperativity is transferrable from O to S containing monomers and to what extent catalyst selection criteria and the ROCOP mechanism itself are affected by periodic trends.…”