Various α,β-unsaturated carbonyl compounds, such as acrylates and acrylamides, were quantitatively introduced to the terminal chain end of poly(phenylacetylene)s by C-C bond formation with terminal organorhodium(I) species formed in the living polymerization of phenylacetylenes with a rhodium-based multicomponent catalytic system that we have recently developed, when these carbonyl compounds were used as terminating reagents. This enables the facile and versatile synthesis of stereoregular telechelic poly(phenylacetylene)s with various functional groups at both the initial and terminal chain ends because the components of aryl boronic acid derivatives used as initiators in our multicomponent catalytic system are quantitatively introduced to the initiating end of the resulting polymer.
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http://dx.doi.org/10.1021/jacs.1c00150 | DOI Listing |
Adv Mater
November 2024
Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, P. R. China.
Poly(lactic acid) (PLA) is a representative biobased and biodegradable aliphatic polyester and a front-runner among sustainable materials. As a semicrystalline thermoplastic, PLA exhibits excellent mechanical and physical properties, attracting considerable attention in commodity and medical fields. Stereochemistry is a key factor affecting PLA's properties, and to this end, the engineering of PLA's microstructure for tailored material properties has been an active area of research over the decade.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland.
-selective ring-opening metathesis polymerization (ROMP) with the commercial Grubbs "nitrato catalyst" has shown promise for synthesizing stereoregular materials, but it comes with the drawback of losing control over the molecular weight due to the poor initiation rate of the catalyst and the need for stoichiometric ruthenium complex loading. To address these issues, we developed a chain transfer polymerization method that allows for the catalytic synthesis of polymers while controlling the degree of polymerization. This allowed us to produce shorter polymers with exceptional chain-end control.
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 PDFPolymers (Basel)
September 2024
CNR-Istituto di Scienze e Tecnologie Chimiche "Giulio Natta" (SCITEC), Via A. Corti 12, I-20133 Milano, Italy.
Some syndiotactic-rich polyolefins, generally difficult to synthesize through stereospecific polymerization of the corresponding monomers, were prepared by homogeneous non-catalytic hydrogenation of syndiotactic 1,2 poly(1,3-diene)s with diimide, arising from thermal decomposition of p-toluene-sulfonyl-hydrazide. All the polymers synthesized were structurally characterized by means of several analytical techniques, such as FT-IR, NMR (H, C and 2D), DSC, and GPC, and herein illustrated.
View Article and Find Full Text PDFMolecules
June 2024
Graduate School of Science, Osaka University, Toyonaka 560-0043, Osaka, Japan.
Since the discovery of metal-catalyzed azide-alkyne cycloadditions, 1,2,3-triazoles have been widely used as linkers for various residues. 1,2,3-Triazole is an aromatic five-membered cyclic compound consisting of three nitrogen and two carbon atoms with large dipoles that absorb UV light. In the past decade, we have been working on the synthesis of dense triazole polymers possessing many 1,2,3-triazole residues linked through a carbon atom in their backbone as a new type of functional polymer.
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