Polysiloxane-encapsulated "Pd"-nanoclusters were generated by reduction of Pd(OAc)(2) with polymethylhydrosiloxane, which functions as a reducing agent as well as a capping material for production and stabilization of catalytically active "Pd"-nanoparticles. Chemoselective hydrogenation of functional conjugated alkenes was achieved by in-situ- or ex-situ-generated polysiloxane-stabilized "Pd"-nanoclusters under mild reaction conditions in high yields. Electron microscopy, UV-vis, and NMR studies of the reaction mixture during the catalytic transformation were performed and, in conjunction with catalyst poisoning experiments, demonstrated unequivocally the role of polysiloxane-encapsulated "Pd"-nanoclusters as the real catalytic species. The recyclability of the "Pd"-nanoclusters was established by reusing the solid left after the reaction.
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http://dx.doi.org/10.1021/ja049604j | DOI Listing |
Mol Omics
December 2024
Department of Chemistry and Biochemistry, University of Texas at Arlington, Box 19065, 700 Planetarium Place, Room 130, Arlington, TX 76019, USA.
Designing reagents for protein labeling is crucial for investigating cellular events and developing new therapeutics. Historically, much effort has been focused on labeling lysine and arginine residues due to their abundance on the protein periphery. The chemo-selectivity of these reagents is a challenging yet crucial parameter for deciphering properties specifically associated with the targeted amino acid.
View Article and Find Full Text PDFJ Org Chem
December 2024
College of New Energy, State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao 266580, P. R. China.
The photocatalytic dearomative 1,4-hydroboration of naphthalenes with an N-heterocyclic carbene borane (NHC-BH) complex was reported herein with controllable regioselectivity and chemoselectivity. This protocol yielded a wide range of naphthalene derivatives bearing various functional groups, notably bioactive compounds. Hydroboration occurred through the cooperation of photoredox and hydrogen atom transfer via boryl radical addition to naphthalene and further selective protonation.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Univ. Grenoble Alpes, CNRS, CERMAV, Grenoble 38000, France.
Hydrogels with antibacterial activities have the potential for many biomedical applications, such as wound healing, because of their capacity to maintain a moist environment and prevent infections. In this work, an ultrasound-induced supramolecular hydrogel consisting of easily accessible reducing-end-free glucosaminylbarbiturate-based hydrogelators that serve the fabrication of silver nanoparticles (AgNPs), excluding the addition of any external reducing or stabilizing agents, has been developed. The innovative synthetic approach relied on the use of -disubstituted barbituric acid derivatives as a versatile chemical platform that site-selectively reacted with the amino function of glucosamine.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
The homogeneous catalytic hydrogenation of benzo-fused heteroarenes generally provides partially hydrogenated products wherein the heteroaryl ring is preferentially reduced, such as quinoline hydrogenation, leading to 1,2,3,4-tetrahydroquinoline. Herein, we report a carbocycle-selective hydrogenation of fused -heteroarenes (quinoline, isoquinoline, quinoxaline, etc.) using the Ru complex of a chiral spiroketal-based diphosphine (SKP) as the catalyst, affording the corresponding 5,6,7,8-tetrahydro products in high chemoselectivities.
View Article and Find Full Text PDFChemSusChem
December 2024
Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas (UPV-CSIC), Avda. de los Naranjos s/n, 46022, Valencia, Spain.
The endeavor of sustainable chemistry has led to significant advancements in green methodologies aimed at minimizing environmental impact while maximizing efficiency. Herein, a straightforward synthesis of benzimidazoles by reductive coupling of o-dinitroarenes with aldehydes is reported for the first time in aqueous media while using a non-noble metal catalyst. This work demonstrates that the combination of nitrogen and phosphorous ligands in the synthesis of supported heteroatom-incorporated Co nanoparticles is crucial for obtaining the desired benzimidazoles.
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