The electronic effects of nitrogen donors in zinc catalysts for ring-opening polymerization of cyclic esters were investigated. Alkyl and benzyloxy zinc complexes supported by tridentate diamino- and aminoimino phenolate ligands were synthesized, and their solid-state and solution structures characterized. The solution-state structures showed that the alkyl complexes are mononuclear, while the alkoxy complexes are dimeric with the ligands coordinated with different denticities depending on the nature of the ligand donors. The catalytic activities of these compounds toward the ring-opening polymerization of racemic lactide were studied and showed that catalysts with secondary and imine nitrogen donors are more active than analogues with tertiary amines.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.inorgchem.6b01722 | DOI Listing |
ISME Commun
January 2025
Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University, Beijing 100871, China.
Rivers serve important functions for human society and are significantly impacted by anthropogenic nutrient inputs (e.g. organic and sulfur compounds).
View Article and Find Full Text PDFFront Pharmacol
January 2025
Department of Pathophysiology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
Introduction: The risk of kidney fibrosis is significantly elevated in individuals with diabetes, chronic nephritis, trauma, and other underlying conditions. Concurrently, human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) and their extracellular vesicles (MSC-Exos) have gained prominence in regenerative medicine. In light of these observations, we are undertaking a meta-analysis to elucidate the influence of hUCB-MSCs and MSC-Exos on kidney fibrosis.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Torino, ITALY.
Ammonia electrosynthesis through the lithium-mediated approach has recently reached promising results towards high activity and selectivity in aprotic media, reaching high Faradaic efficiency (FE) values and NH3 production rates. To fasten the comprehension and optimization of the complex lithium-mediated nitrogen reduction system, for the first time a multivariate approach is proposed as a powerful tool to reduce the number of experiments in comparison with the classical one-factor-at-a-time approach. Doehlert design and surface response methodology are employed to optimize the electrolyte composition for a batch autoclaved cell.
View Article and Find Full Text PDFChemistry
January 2025
The University of Western Ontario, Department of Chemistry, 1151 Richmond St. N., N6A 5B7, London, CANADA.
The exploration of phosphorus-nitrogen heterocycles derived from chelating N-donor ligands is an area of research that has lagged behind the development of similar heterocycles based on other main group elements, most notably boron. The fact that phosphorus and nitrogen are both group 15 elements and that their compounds are most commonly viewed as Lewis bases likely contributes to this observation. However, through judicious ligand design and creative use of phosphorus sources that render phosphorus as Lewis acidic and/or electron poor, a variety of heterocyclic architectures are possible.
View Article and Find Full Text PDFJ Biotechnol
January 2025
Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China; The Research Center of Chiral Drugs, Shanghai Frontiers Science Center for TCM Chemical Biology, Innovation Research Institute of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China. Electronic address:
Chiral azacyclic amine derivatives occupy a vital role of nitrogen-containing compounds, due to serve as foundational motifs in numerous pharmaceuticals and bioactive substances. Novel complementary enantioselective reductive aminases IRED9 and IRED11 were unveiled through comprehensive gene mining from Streptomyces viridochromogenes and Micromonospora echinaurantiaca, respectively, which both demonstrated enantiomeric excess (ee) values and conversion ratios of up to 99 % towards N-Boc-3-pyridinone (NBPO) and cyclopropylamine. IRED9 exhibited the highest activity at pH 8.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!