Bench-stable complexes of the type [Ir(COD)(NHC)Cl] (NHC = N-heterocyclic carbene) have been investigated within the field of hydrogen isotope exchange. By employing a sterically encumbered NHC within such complexes and catalyst loadings of only 5 mol%, moderate to high deuterium incorporations were achieved across a range of aromatic ketones and nitrogen-based heterocycles. The simple and synthetically accessible catalysts reported herein present alternatives to phosphine-based species and increase the available labelling systems with respect to established iridium-based isotope exchange methodologies.
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http://dx.doi.org/10.1002/jlcr.3084 | DOI Listing |
Nat Commun
January 2025
Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Montréal, QC, H3T 1J4, Canada.
Intense research on founding members of the RAS superfamily has defined our understanding of these critical signalling proteins, leading to the premise that small GTPases function as molecular switches dependent on differential nucleotide loading. The closest homologs of H/K/NRAS are the three-member RRAS family, and interest in the MRAS GTPase as a regulator of MAPK activity has recently intensified. We show here that MRAS does not function as a classical switch and is unable to exchange GDP-to-GTP in solution or when tethered to a lipid bilayer.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Universitat Bern, Department of Chemistry and Biochemistry, Freiestrasse 3, 3012, Bern, SWITZERLAND.
Isotope Exchange processes are becoming the preferred way to prepare isotopically labelled molecules, avoiding the redesign of multistep synthetic protocols. In the case of deuterium incorporation, the most used strategy has employed transition metals, that offer high reactivity under mild reaction conditions. Despite their success, the trade-off is that these metals are precious, and often exhibit high toxicity.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Ulsan National Institute of Science and Technology, Department of Chemistry, UNIST GIL 50, 44919, Ulsan, KOREA, REPUBLIC OF.
Efficient separation of hydrogen isotopes, especially deuterium (D2), is pivotal for advancing industries such as nuclear fusion, semiconductor processing, and metabolic imaging. Current technologies, including cryogenic distillation and Girdler sulfide processes, suffer from significant limitations in selectivity and cost-effectiveness. Herein, we introduce a novel approach utilizing an imidazolium-based Metal-Organic Framework (MOF), JCM-1, designed to enhance D2/H2 separation through temperature-dependent gate-opening controlled by ion exchange.
View Article and Find Full Text PDFIndian J Nucl Med
November 2024
Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India.
Background: Fluorine-18 (F) flumazenil (FMZ) has been synthesized using various precursors, and its role has been explored in imaging Gamma-aminobutyric acid-A receptors.
Aim And Objective: The main objective was to synthesize (F) FMZ using isotopic substitution.
Materials And Methods: Around 18 ± 2 GBq was added to the module, dried, and radiolabeling was standardized with 3.
Rapid Commun Mass Spectrom
March 2025
School of Earth, Environment & Society, McMaster University, Hamilton, Ontario, Canada.
Rationale: Carbonate minerals are one of the most popular samples for an automated sample preparation system for CF-IRMS, such as GasBench II and iso FLOW, but no standardized analytical protocols exist. This study gives guidelines on optimal analytic conditions for carbon and oxygen isotope analysis of Ca-Mg carbonates when using the carbonate-phosphoric acid reaction method.
Methods: Calcite (CaCO-McMaster Carrara), dolomite (CaMg(CO)-MRSI Dolomite), and magnesite (MgCO-ROM Brazil Magnesite) with two grain size fractions (< 74 and 149-250 μm) were reacted with 103% (specific gravity of 1.
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