Unprecedented enantioselective resolution copolymerization of racemic cis-internal epoxides and anhydrides was mediated by dinuclear aluminum complexes with multiple chirality, affording optically active polyesters with two contiguous stereogenic centers, and the unreacted substrates in good enantioselectivity. Unexpected stereoconvergence is observed in this resolution copolymerization, where the selectivity factor for the enantioselective formation of copolymer significantly exceeds the kinetic resolution coefficient based on the unreacted epoxide at various conversions. Catalytic activity and copolymer enantioselectivity are strongly influenced by the phenolate ortho-substituents of the ligand set, as well as the axial linker and its chirality. An enantiopure binaphthol-linked bimetallic Al complex allows stereoconvergent access to the stereoregular semi-crystalline polyesters and a concomitant kinetic resolution of the epoxide substrates.
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http://dx.doi.org/10.1002/anie.202011259 | DOI Listing |
Nanoscale
January 2025
Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52074 Aachen, Germany.
Microgels are versatile materials with applications across biomedicine, materials science, and beyond. Their controllable size and composition enables tailoring specific properties, yet characterizing their internal structures on the nanoscale remains challenging. Super-resolution fluorescence microscopy (SRFM) effectively analyzes sub-μm structures, including microgels, offering a tool for investigating more complex systems such as core-shell microgels.
View Article and Find Full Text PDFSSNA-1 is a fibrillar protein localized at the area where dynamic microtubule remodeling occurs including centrosomes. Despite the important activities of SSNA1 to microtubules such as nucleation, co-polymerization, and lattice sharing microtubule branching, the underlying molecular mechanism have remained unclear due to a lack of structural information. Here, we determined the cryo-EM structure of SSNA-1 at 4.
View Article and Find Full Text PDFNat Nanotechnol
November 2024
Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Centre, College of Chemistry and Molecular Engineering, Peking University, Beijing, People's Republic of China.
Olefin metathesis, as a powerful metal-catalysed carbon-carbon bond-forming method, has achieved considerable progress in recent years. However, the complexity originating from multicomponent interactions has long impeded a complete mechanistic understanding of olefin metathesis, which hampers further optimization of the reaction. Here, we clarify both productive and hidden degenerate pathways of ring-closing metathesis by focusing on one individual catalyst, using a sensitive single-molecule electrical detection platform.
View Article and Find Full Text PDFAdv Healthc Mater
December 2024
Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Department of Engineering Mechanics, Zhejiang University, Hangzhou, 310027, China.
Angew Chem Int Ed Engl
January 2025
Thomas Lord Department of Mechanical Engineering & Material Science, Duke University, Durham, NC, USA.
Digital light processing (DLP) printing forms solid constructs from fluidic resins by photochemically crosslinking polymeric resins with reactive functional groups. DLP is used widely due to its efficient, high-resolution printing, but its use and translational potential has been limited in some applications as state-of-the-art resins experience unpredictable and anisotropic part shrinkage due to the use of solvent needed to reduce resin viscosity and layer dependent crosslinking. Herein, poly(allyl glycidyl ether succinate) (PAGES), a low viscosity, degradable polyester, was synthesized by ring opening copolymerization and used in combination with degradable thiol crosslinkers to afford a solvent free resin that can be utilized in DLP printing.
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