Selective catalytic α-deuteration of aliphatic nitriles using deuterium oxide as a deuterium source is reported. A PNP-ruthenium pincer complex catalyzed the α-deuteration of aliphatic nitriles including acetonitrile. Efficient deuteration occurred with a low catalyst load (0.2 to 0.5 mol%) and under mild conditions. A [2+2] cycloadduct formation from nitrile functionality and a deprotonated catalytic intermediate, followed by an imine-enamine tautomerization and a H/D exchange between the enamine intermediate and deuterium oxide leading to the selective deuteration at the α-position of the nitrile, is proposed as a plausible reaction mechanism.
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http://dx.doi.org/10.1039/c8cc03971b | DOI Listing |
Nat Chem Biol
January 2025
Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro, NC, USA.
Peptide cyclization is a defining feature of many bioactive molecules, particularly in the ribosomally synthesized and post-translationally modified peptide (RiPP) family of natural products. Although enzymes responsible for N- to C-terminal macrocyclization, lanthipeptide formation or heterocycle installation have been well documented, a diverse array of cyclases have been discovered that perform crosslinking of aromatic side chains. These enzymes form either biaryl linkages between two aromatic amino acids or a crosslink between one aliphatic amino acid and one aromatic amino acid.
View Article and Find Full Text PDFSci Rep
January 2025
Climate and Environmental Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.
Abiotic H and hydrocarbons are found in fluids discharged from ultramafic-hosted hydrothermal vents. Beneath the hydrothermal vents, abiotic H and hydrocarbons can be formed by serpentinization reactions and Fischer-Tropsch-type hydrocarbon-forming reactions, respectively, over ultramafic rocks. However, the source rocks that form abiotic H and hydrocarbons may extend to broader subsurface rocks.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
School of Environmental Science and Engineering, Southwest Jiaotong University, Sichuan, Chengdu 611756, China. Electronic address:
The ultraviolet-activated peroxymosnofulate (UV/PMS) system, an effective advanced oxidation process for removing dissolved organic matter (DOM) from wastewater, is limited by high chloride ion (Cl) concentrations in landfill leachate. This study used Fourier transform ion cyclotron resonance mass spectrometry to explore the transformation of DOM in the UV/PMS system with a high Cl concentration. The results revealed that elevated Cl levels generate reactive chlorine species, including chlorine radicals, dichlorine radicals, and hypochlorous acid/hypochlorite, reducing the total organic carbon (TOC) removal efficiency of Suwannee River natural organic matter (SRNOM) from 78.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Electrical Engineering, Tsinghua University, Beijing, 100084, China.
As an effective method to enhance the dielectric performance of polyolefin materials, polar side group modification has been extensively applied in the insulation and energy storage materials of electrical and electronic systems. In this work, two side groups with different topological structures were adopted, namely, vinyl acetate (VAc, aliphatic chain) and -vinyl-pyrrolidone (NVP, saturated ring), to modify polypropylene (PP) chemical grafting, and the effects of structural topology of the polar side group on the microscopic and macroscopic characteristics of PP, particularly on its electrical anti-breakdown ability, were investigated. Experimental results showed that the side group structural topology directly affected the crystallization and thermal properties of PP.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
Department of Materials Science and Engineering, National University of Singapore (NUS), 9 Engineering Drive 1, Singapore, 117575, Singapore.
The modification of thermoplastic polymers is frequently impeded by the inherent contradiction between their toughness and strength. In this study, an effective strategy to significantly improve the mechanical properties of ductile polymers by simply adding a complimentary rigid polymer is introduced. This work uses a semi-crystalline polymer aliphatic polyketone (POK) as the matrix material and a small quantity of polymethyl methacrylate (PMMA) as the rigid polymer, through establishing molecular chain entanglements at the interface to produce POK/PMMA blends with exceptional mechanical property.
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