A clean, mild and sustainable method for the functionalization of pyridines and their analogues is reported. A zinc-based Lewis acid is used to activate pyridine and its analogues towards nucleophilic aromatic substitution, conjugate addition, and cyclization reactions by binding to the nitrogen on the pyridine ring and activating the pyridine ring core towards further functionalization.
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http://dx.doi.org/10.1002/cssc.201403154 | DOI Listing |
Crit Care
January 2025
Division of Digestive and Liver Diseases, Columbia University Irving Medical Center, 630 West 168th Street, P&S 3-401, New York, NY, 10032, USA.
Background: Patients admitted to the intensive care unit (ICU) often have gut colonization with pathogenic bacteria and such colonization is associated with increased risk for death and infection. We conducted a trial to determine whether a prebiotic would improve the gut microbiome to decrease gut pathogen colonization and decrease downstream risk for infection among newly admitted medical ICU patients with sepsis.
Methods: This was a randomized, double-blind, placebo-controlled trial of adults who were admitted to the medical ICU for sepsis and were receiving broad-spectrum antibiotics.
ACS Appl Mater Interfaces
January 2025
School of Chemical Engineering, Zhengzhou University, Zhengzhou 450001, P. R. China.
Defective MOFs have been identified as promising candidates for efficient membrane-based separation applications. However, the utilization of defective MOFs in membrane gas separation is still in its infancy due primarily to the inefficient molecular differentiation induced by structural defects. Herein, we report a strategic combination of ionic liquid (IL) and defective UiO-66-NH MOF to ameliorate the CO/N selectivity within the highly permeable PIM-1 polymer.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
School of Chemistry and Chemical Engineering, Key Laboratory of Colloid and Interface Chemistry of the Ministry of Education, Shandong University, Jinan 250100, P. R. China.
Herein, we describe a hexavalent tellurium-based chalcogen bonding catalysis platform capable of addressing reactivity and selectivity issues. This research demonstrates that hexavalent tellurium salts can serve as a class of highly active chalcogen bonding catalysts for the first time. The tellurium centers in these hexavalent catalysts have only one exposed interaction site, thus providing a favorable condition for the controlling of reaction selectivity.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
The bifunctional mechanism, involving multiactive compositions to simultaneously dissociate water molecules and optimize intermediate adsorption, has been widely used in the design of catalysts to boost water electrolysis for sustainable hydrogen energy production but remains debatable due to difficulties in accurately identifying the reaction process. Here, we proposed the concept of well-defined Lewis pairs in single-atom catalysts, with a unique acid-base nature, to comprehensively understand the exact role of multiactive compositions in an alkaline hydrogen evolution reaction. By facilely adjusting active moieties, the induced synergistic effect between Lewis pairs (M-P/S/Cr pairs, M = Ru, Ir, Pt) can significantly facilitate the cleavage of the H-OH bond and accelerate the removal of intermediates, thereby switching the rate-determining step from the Volmer step to the Heyrovsky step.
View Article and Find Full Text PDFNat Commun
January 2025
National Key Laboratory of Electronic Films and Integrated Devices, School of Integrated Circuit Science and Engineering, University of Electronic Science and Technology of China, Chengdu, P. R. China.
Suppressing deep-level defects at the perovskite bulk and surface is indispensable for reducing the non-radiative recombination losses and improving efficiency and stability of perovskite solar cells (PSCs). In this study, two Lewis bases based on chalcogen-thiophene (n-Bu4S) and selenophene (n-Bu4Se) having tetra-pyridine as bridge are developed to passivate defects in perovskite film. The uncoordinated Pb and iodine vacancy defects can interact with chalcogen-concave group and pyridine group through the formation of the Lewis acid-base adduct, particularly both the defects can be surrounded by concave molecules, resulting in effective suppression charge recombination.
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