Search for: All records

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). 

With the goal of generating hetero‐redox levels on metals as well as on nitric oxide (NO), metallodithiolate (N₂S₂)Co^III(NO⁻), N₂S₂=N,N‐ dibenzyl‐3,7‐diazanonane‐1,9‐dithiolate, is introduced as ligand to a well‐characterized labile [Ni⁰(NO)⁺] synthon. The reaction between [Ni⁰(NO⁺)] and [Co^III(NO⁻)] has led to a remarkable electronic and ligand redistribution to form a heterobimetallic dinitrosyl cobalt [(N₂S₂)Ni^II∙Co(NO)₂]⁺complex with formal two electron oxidation state switches concomitant with the nickel extraction or transfer as Ni^IIinto the N₂S₂ligand binding site. To date, this is the first reported heterobimetallic cobalt dinitrosyl complex.

 

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.