A Lewis base/Bronsted acid catalyzed aromatic sulfenylation is reported. These studies demonstrated that the incorporation of electron-rich sulfenyl groups proceeded in the absence of a Lewis base, with kinetic studies indicating an autocatalytic mechanism. The incorporation of electron-poor sulfenyl groups demonstrated little autocatalysis necessitating the use of a Lewis base. This method proved amenable to diverse arenes and heterocycles and was effective in the context of the late-stage functionalization of biologically active small molecules.
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http://dx.doi.org/10.1021/acs.orglett.8b01066 | DOI Listing |
Sci Rep
December 2024
China Special Equipment Inspection and Research Institute, Beijing, 100000, China.
Catalytic CO desorption has emerged as a crucial strategy for enhancing the efficiency of CO capture and reducing energy requirements, thereby advancing chemical absorption methods. This study examines the catalytic effectiveness of titanium pyrophosphate (TiPO) in improving monoethanolamine (MEA)-based CO absorption and desorption processes, comparing its performance with other titanium-based catalysts, including titanium dioxide (TiO), titanium tetrahydroxide (TiO(OH)), and titanium carbide (TiC). In TiPO, Ti ions function as Lewis acid sites by accepting electron pairs (LASs), PO anions act as proton carriers, facilitating rapid proton transfer as Lewis base sites (LBSs), and active hydroxyl groups on the surface, resulting from water molecule dissociation or the deprotonation reaction, function as Brönsted acid sites (BASs).
View Article and Find Full Text PDFJ Phys Chem B
December 2024
College of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, P.R. China.
The hydrogenolysis of lignin model compounds (MCs) into high-value chemicals has received increasing attention, but their catalytic reaction mechanisms are not yet very clear. Here, we report the reaction mechanisms of the hydrogenolysis of MC into 4-acetylanisole (AAL) and guaiacol (GAL) catalyzed by LRuCl (L = 4'-(4-methoxyphenyl)-2,2':6',2″-terpyridine) with MC, H, and 1-phenylethan-1-ol (PEO) as the H-sources in aqueous solution with the Bro̷nsted base (NaOH), at the M06/def2-TZVP, 6-311++G (d,p) theoretical level, namely, RS-Self, RS-H, and RS-PEO, respectively. After dissociation in NaOH aqueous solution, the LRuCl compound can form a stable complex LRh (OH) as the initial catalytically active species.
View Article and Find Full Text PDFChemSusChem
November 2024
State Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide & Agricultural Bioengineering, Ministry of Education, State-Local Joint Laboratory for Comprehensive Utilization of Biomass, Center for R&D of Fine Chemicals, Guizhou University, Guiyang, 550025, China.
The direct production of value-added chemicals from biomass via multiple conversion processes with a sole renewable solid catalyst is promising for carbon-neutral development while challenging. Herein, a series of novel bioresourced organic-inorganic hybrid materials were synthesized from bio-based ascorbic acid (Vc), zirconium chloride (ZrCl) and p-toluenesulfonic acid (p-TSA) through a facile solvothermal process. The as-prepared Zr-Vc-3 catalyst with Vc, ZrCl, and p-TSA in the 1 : 1:0.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
Department of Chemical and Biomolecular Engineering, National University of Singapore, 117585 Singapore.
We report the design and synthesis of the first aliphatic covalent organic framework (COF), NUS-119, and its subsequent conversion to NUS-120, marking the first fully saturated COF. NUS-119 is built by imine-linkages exhibiting high crystallinity and porosity, achieved by using a Lewis acid as a reaction modulator to circumvent compatibility issues between the Brønsted acid and the strong basic monomer. The structure was successfully solved using 3D microelectron diffraction (microED) techniques.
View Article and Find Full Text PDFACS Omega
October 2024
Angadi Institute of Technology and Management (AITM), Savagaon Road, Belagavi, Karnataka 5800321, India.
Heterocyclic compounds are of great interest in our daily lives. They are widely distributed in nature and are synthesized in laboratories. Heterocycles play an important role in the metabolism of all living cells, including vitamins and coenzyme precursors like thiamine and riboflavin.
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