Copolymerization of CO₂and meso epoxides using enantioselective β-diiminate catalysts: a route to highly isotactic polycarbonates

Dinuclear Metal Complex-Mediated Formation of CO2-Based Polycarbonates

“…This coordination is proposed to weaken/labilise the group X and accelerate both initiation and propagation [40,49]. In contrast, some of the β-diiminate Zn complexes and macrocyclic complexes do not require, or benefit from, the addition of such cocatalysts [63,65,76,77,85].…”

“…These catalysts show good TOFs, up to 190 h À1 at 22 C and 8 atm of CO 2, and produced polymers with high iso-selectivity (ee >90%). Variation of the amino substitution with the (S, S)-cyclohexyl-triiso-propylsilyl ether group increased the enantioselectivity to achieve a ee of 94% at 0 C [76].…”

“…For cyclohexene oxide (CHO), catalysts able to exert stereocontrol enable the production of iso-and syndiotactic polymers. Recently, several catalysts, most notably metal salen and β-diiminate complexes, have proved capable of exerting excellent control over both the regio-and stereochemistry [34,55,72,76,[91][92][93][94][95][96][97][98][99][100][101][102][103][104].…”

“…2). These include porphyrins and the closely related corroles [55,59,[68][69][70][71][72][73][74]; Schiff base ligands, most commonly salens/salans [40,46,75]; β-diiminates [76][77][78][79][80][81][82]; and (macrocyclic) phenoxy- amine ligands, including deliberately dinucleating macrocycles [63,65,[83][84][85][86][87][88]. The first two classes are dianionic and are largely targeted towards M(III) oxidation states, whereas the latter two are often used to prepare M(II) catalysts.…”

Chemoselective Alternating Copolymerization of Limonene Dioxide and Carbon Dioxide: A New Highly Functional Aliphatic Epoxy Polycarbonate

“…To our best knowledge, this is the first report on the synthesis of such linear, non-gelling epoxide-functionalized PCs, at high monomer conversion using a diepoxide and CO 2 . [11] Based on the conditions used for the LMO/CO 2 system, initial copolymerizations with commercially available LDO were performed in bulk at 25 8C under 10 bar of CO 2 using 1.0 mol % of the zinc catalyst (Et-BDI)Zn[N(SiMe 3 ) 2 ] (see Scheme 1).…”