The preparation and reprocessing of an epoxy vitrimer material is performed in a fully biocatalyzed process wherein network formation and exchange reactions are promoted by a lipase enzyme. Binary phase diagrams are introduced to select suitable diacid/diepoxide monomer compositions overcoming the limitations (phase separation/sedimentation) imposed by curing temperature inferior than 100 °C, to protect the enzyme. The ability of lipase TL, embedded in the chemical network, to catalyze efficiently exchange reactions (transesterification) is demonstrated by combining multiple stress relaxation experiments at 70-100 °C and complete recovery of mechanical strength after several reprocessing assays (up to 3 times). Complete stress relaxation ability disappears after heating at 150 °C, due to enzyme denaturation. Transesterification vitrimers thus designed are complementary to those involving classical catalysis (e.g., using the organocatalyst triazabicyclodecene) for which complete stress relaxation is possible only at high temperature.
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http://dx.doi.org/10.1021/acsmacrolett.2c00715 | DOI Listing |
J Org Chem
January 2025
Department of Chemistry and Chemical Engineering, Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, Liaocheng University, Liaocheng 252059, China.
Multipalladium clusters possess peculiar structures and synergistic effects for reactivity and selectivity. Herein, -symmetric tripalladium clusters (, 0.5 mol %) afford C-regioselective SMCC of 2,4-dibromopyridine with phenylboronic acids or pinacol esters (C:C up to 98:1), in contrast to Pd(OAc) in ligand-free conditions.
View Article and Find Full Text PDFSmall
January 2025
Department of Materials Science and Engineering, and Center for Functional Photonics (CFP), City University of Hong Kong, Hong Kong SAR, 999077, P. R. China.
Metal halide perovskite nanoplatelets (NPls) possess ultra-narrow photoluminescence (PL) bands tunable over the entire visible spectral range, which makes them promising for utilization in light-emitting diodes (LEDs) with spectrally pure emission colors. This calls for development of synthetic methods toward perovskite NPls with a high degree of control over both their thickness and lateral dimensions. A general strategy is developed to obtain such monodisperse CsPbI NPls through the control over the halide-to-lead ratio during heating-up reaction.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Valladolid, Spain.
This article reports a theoretical study on the halogen exchange reactions YX + CHO → Y + XCHO (with Y = F, Cl, Br; X = Cl, Br, I) carried out at a high level of accuracy using coupled-cluster based methodologies including CCSD(T)-F12, CCSD(T)/CBS and CCSDT(Q). Most of the reactions are exothermic at room temperature, with the exception of the reactions FI + CHO → F + ICHO and ClI + CHO → Cl + ICHO. Exothermicity follows two concurrent trends established by the strength of the bonds being cleaved and formed: Y = F < Cl < Br (X-Y bond strength) and X = Cl > Br > I (C-X bond strength).
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave, Madison, Wisconsin 53706, United States.
Although alkyl alcohols and aryl chlorides are the two most abundant substrate pools for cross-electrophile coupling, methods to couple them remain limited. Herein we demonstrate a simple procedure for the in situ deoxychlorination of alcohols followed by XEC with aryl chlorides. A broad substrate scope can be achieved by tuning the rate of the reaction via halide exchange.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Yunnan Key Laboratory of Modern Separation Analysis and Substance Transformation, College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650500, China.
We successfully synthesize monodisperse sulfhydryl-modified mesoporous organosilica nanospheres (MONs-SH) via one-step hydrolytic condensation, where cetyltrimethylammonium chloride and dodecyl sulfobetaine are employed as dual-template agents with (3-mercaptopropyl)triethoxysilane and 1,2-bis(triethoxysilyl)ethane as the precursors and concentrated ammonia as the alkaline catalyst. The prepared MONs-SHs deliver a large specific surface area (729.15 m g), excellent monodispersity, and homogeneous particle size.
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