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ABSTRACT:The synthesis, characterization, and reactivity of an aluminum alkoxide complex supported by a ferrocene-based ligand, (thiolfan*)Al(O t Bu) (1 red , thiolfan* = 1,1'-di(2,4-di-tert-butyl-6-thiophenoxy)ferrocene), are reported. The homopolymers of L-lactide (LA), ε-caprolactone (CL), δ-valerolactone (VL), cyclohexene oxide (CHO), trimethylene carbonate (TMC), and their copolymers were obtained in a controlled manner by using redox reagents. Detailed DFT calculations and experimental studies were performed to investigate the mechanism. Mechanistic studies show that after the insertion of the first monomer, the coordination effect of the carbonyl group, which has usually been ignored in previous reports, can significantly change the energy barrier of the propagation steps, thus playing an important role in polymerization and copolymerization processes.

The synthesis of the first alkoxide-bridged indium complex supported by a chiral dinucleating ligand platform (1), along with its zinc analogue (2), is reported. Both complexes are synthesized in a one-pot reaction starting from a chiral dinucleating bis(diamino)phenolate ligand platform, sodium ethoxide, and respective metal salts. The dinucleating indium analogue (7) based on an achiral ligand backbone is also reported. Indium complexes bearing either the chiral or achiral ligand catalyze the ring-opening polymerization of racemic lactide (rac-LA) to afford highly heterotactic poly(lactic acid) (PLA; Pr > 0.85). The indium complex bearing an achiral ligand affords essentially atactic PLA from meso-LA. The role of the dinucleating ligand structure in catalyst synthesis and polymerization activity is discussed.

Chemical products, such as plastics, solvents, and fertilizers, are essential for supporting modern lifestyles. Yet, producing, using and disposing of chemicals creates adverse environmental impacts which threaten the industry's license to operate. This study presents seven planet compatible pathways towards 2050 employing demand-side and supply-side interventions with total investment costs of US$1.2-3.7 billion. Resource efficiency and circularity interventions reduce global chemicals demand by 23–33% and are critical for mitigating risks associated with using fossil feedstocks and carbon capture and sequestration, and constraints on available biogenic and recyclate feedstocks. Replacing fossil feedstocks with biogenic/air-capture sources, shifting carbon destinations from atmosphere to ground, and electrifying/decarbonizing energy supply for production technologies, could enable net negative emissions of 200 MtCO2eq yr-1, while still delivering essential chemical-based services to society.

Chemical products, such as plastics, solvents, and fertilizers, are essential for supporting modern lifestyles. Yet, producing, using and disposing of chemicals creates adverse environmental impacts which threaten the industry's license to operate. This study presents seven planet compatible pathways towards 2050 employing demand-side and supply-side interventions with total investment costs of US$1.2-3.7 billion. Resource efficiency and circularity interventions reduce global chemicals demand by 23–33% and are critical for mitigating risks associated with using fossil feedstocks and carbon capture and sequestration, and constraints on available biogenic and recyclate feedstocks. Replacing fossil feedstocks with biogenic/air-capture sources, shifting carbon destinations from atmosphere to ground, and electrifying/decarbonizing energy supply for production technologies, could enable net negative emissions of 200 MtCO2eq yr-1, while still delivering essential chemical-based services to society.