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Synthetic transformation of d -xylose into a four-membered cyclic ether allows for reactions with carbon dioxide (CO 2 ) leading to linear polycarbonates by either a one-step ring-opening copolymerisation (ROCOP) directly, or by sequential isolation of a preformed six-membered cyclic carbonate followed by ring-opening polymerisation (ROP). 

The synthesis of poly(propylene carbonate) with 100% 13C-labeled carbonate carbons is reported. The 𝑣CO3 vibration is shifted 45 cm−1 lower than that observed in its 12C analog. This lowering of the 𝑣CO3 vibrational mode of the copolymer provides a window for observing νNO stretching motions in incorporated dinitrosyl iron complexes. 

Carbon dioxide based polymers synthesized from the metal-catalyzed copolymeriation of epoxides and CO 2 containing the terpyridine ligand as an end group are reported. The strategy used was to carry out the polymerization in the presence of a carboxylic acid derivative of terpyridine, 4′-(4-carboxyphenyl)-2,2′:6′,2′′-terpyridine (HL), as a chain transfer agent. The epoxide monomer possessing a vinyl substituent, allyl glycidyl ether (AGE), was copolymerized with CO 2 employing a (salen)Co( iii ) catalyst to afford a polycarbonate which upon the addition of mercaptoacetic acid across the double bond, followed by deprotonation, yielded a water soluble polymer. In a similar manner, the sequential formation of a diblock terpolymer produced from propylene oxide, AGE, and CO 2 provided a amphiphilic polycarbonate which self-assembled upon addition to water to form micelle nanostructures. The molecular weights of these CO 2 -derived polycarbonates were shown to be easily controlled by the quantity of chain transfer agent used. These polymeric ligands were demonstrated to provide a modular design for synthesizing a wide variety of metal complexes as illustrated herein for zinc and platinum derivatives. 

This tutorial deals initially with a comparison of the mechanistic aspects of living and immortal polymerization processes. The living polymerization pathway originated with the anionic polymerization of styrene by Szwarc, whereas immortal polymerization was first described by Inoue for the homopolymerization of epoxides using an aluminum complex. A similar behavior would be anticipated for the copolymerization of epoxides and carbon dioxide catalyzed by well-defined metal complexes. The major difference between these two pathways is rapid and reversible chain transfer reactions involving protic impurities or additives in the latter case, that is, the stoichiometry of the monomer/initiator ratio changes as a function of the nature and concentration of the chain transfer agent (CTA). For instance, in early studies of the copolymerization of epoxides and CO 2 where adventitious water was present in the copolymerization reactions, there was little control of the molecular weight of the resulting copolymer product. Presently, the presence of chain transfer with protic CTAs during the copolymerization of epoxides and CO 2 is a major positive factor in this process's commercialization. Specifically, this represents an efficient production of polyols for the synthesis of CO 2 -based polyurethanes. Studies of the use of various CTAs in the synthesis of designer polymeric materials from CO 2 and epoxides are summarized herein.