An orthogonal combination of cationic and radical RAFT polymerizations is used to synthesize bottlebrush polymers using two distinct RAFT agents. Selective consumption of the first RAFT agent is used to control the cationic RAFT polymerization of a vinyl ether monomer bearing a secondary dormant RAFT agent, which subsequently allows side-chain polymers to be grafted from the pendant RAFT agent by a radical-mediated RAFT polymerization of a different monomer, thus completing the synthesis of bottlebrush polymers. The high efficiency and selectivity of the cationic and radical RAFT polymerizations allow both polymerizations to be conducted in one-pot tandem without intermediate purification.
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http://dx.doi.org/10.1002/anie.202000700 | DOI Listing |
ACS Earth Space Chem
January 2025
School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, U.K.
2-Cyanoindene is one of the few specific aromatic or polycyclic aromatic hydrocarbon (PAH) molecules positively identified in Taurus molecular cloud-1 (TMC-1), a cold, dense molecular cloud that is considered the nearest star-forming region to Earth. We report cryogenic mid-infrared (550-3200 cm) and visible (16,500-20,000 cm, over the ← electronic transition) spectra of 2-cyanoindene radical cations (2CNI), measured using messenger tagging (He and Ne) photodissociation spectroscopy. The infrared spectra reveal the prominence of anharmonic couplings, particularly over the fingerprint region.
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
Herein, we report an electricity-driven activation of aziridine via direct anodic oxidation to give -heterocycles and 1,2-bifunctionalized products by excluding any oxidant/reductant or metal catalyst. Many structurally modified aziridines were employed in the presence of different nitriles. A large variety of nucleophiles were screened to furnish chemoselectively O-alkylated and C-alkylated products.
View Article and Find Full Text PDFInt J Mass Spectrom
February 2025
Department of Chemistry, University of Nevada, 1664 N. Virginia Street, Reno, Nevada 89557, United States.
Free radical-initiated peptide sequencing (FRIPS) is a tandem mass spectrometry technique (MS/MS) that enables radical-based dissociation on instruments only capable of collisional activation. In FRIPS, peptides are chemically-derivatized with a compound that undergoes homolytic cleavage and generates radicals upon collisional activation. These radicals then propagate through the peptide backbone enabling the sequencing of peptide ions.
View Article and Find Full Text PDFACS Omega
January 2025
Department of Chemistry, Federal University of Sergipe, 49400-000 São Cristóvão, SE, Brazil.
Cellulose-based materials are promising adsorbents for pollutants and other classes of compounds. Here, we report the preparation of hydrogels via chemical cross-linking of microcrystalline cellulose oxidized by the 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO). The cross-linking process was carried out in the presence of modifiers such as β-cyclodextrin in order to insert hydrophobic cavities or κ-carrageenan due to the presence of negative charges along the molecular chains.
View Article and Find Full Text PDFMetal oxides are promising catalysts for small molecule hydrogen chemistries, mediated by interfacial proton-coupled electron transfer (PCET) processes. Engineering the mechanism of PCET has been shown to control the selectivity of reduced products, providing an additional route for improving reductive catalysis with metal oxides. In this work, we present kinetic resolution of the rate determining proton-transfer step of PCET to a titanium-doped POV, TiVO(OCH) with 9,10-dihydrophenazine by monitoring the loss of the cationic radical intermediate using stopped-flow analysis.
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