Recent synthetic efforts have uncovered several bond activation pathways mediated by beryllium. Having the highest charge density and electronegativity, the chemistry of beryllium often diverges from that of its heavier alkaline earth metal congeners. Herein, we report the synthesis of a new carbodicarbene beryllacycle (). Compound converts to via an unprecedented cyclic(alkyl)(amino) carbene (CAAC)-promoted ring expansion reaction (RER). While CAAC activates a carbon-beryllium bond, N-heterocyclic carbene (NHC) coordinates to beryllium to give the tetracoordinate complex , which contains the longest C-Be bond to date at 1.856(4) Å. All of the compounds were fully characterized by X-ray crystallography, Fourier transform infrared spectroscopy, and H, C, and Be NMR spectroscopy. The ring expansion mechanism was modeled with both NHC and CAAC using density functional theory calculations. While the activation energy for the observed beryllium ring expansion with CAAC was found to be 14 kJ mol, the energy barrier for the hypothetical NHC RER is significantly higher (199.1 kJ mol).
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http://dx.doi.org/10.1021/acs.inorgchem.9b01643 | DOI Listing |
Rift Valley fever (RVF) is a devastating zoonotic mosquito-borne viral hemorrhagic fever disease that threats human and animal health and biodiversity in Africa, including in Rwanda. RVF is increasingly outbreaking in Africa, leading to devastating impacts on health, socioeconomic stability and growth, and food insecurity in the region, particularly among livestock-dependent communi-ties. This systematic review synthesizes existing evidence on RVF's epidemiology, transmission dynamics, and the prevention and control measures implemented in Rwanda.
View Article and Find Full Text PDFJ Clin Neurosci
January 2025
Department of Neurological Surgery and Rosa Ella Burkhardt Brain Tumor & Neuro-Oncology Center, Cleveland Clinic, Cleveland, OH, USA; Cleveland Clinic Lerner College of Medicine of Case Western Reserve University. Electronic address:
Background And Objective: Radiosurgery can serve as a primary, adjuvant, or salvage treatment modality for cavernous sinus tumors (CST), providing high tumor control. However, particularly with cavernous sinus expansion, there may be insufficient distance from the optic apparatus to perform radiosurgery safely. The internal carotid artery adjacent to the distal dural ring (ICAddr), when enhancing similarly to the CST, can be difficult to delineate, and can lead to over-contouring of target volume near the optic nerve and therefore increasing the risk of radiation-induced optic toxicity.
View Article and Find Full Text PDFRSC Med Chem
January 2025
School of Chemical Sciences, University of Auckland Auckland 1010 New Zealand
Dysregulation of choline phospholipid metabolism and overexpression of phosphatidylcholine-specific phospholipase C (PC-PLC) is implicated in various cancers. Current known enzyme inhibitors include compounds based on a 2-morpholino-5--benzylamino benzoic acid, or hydroxamic acid, scaffold. In this work, 81 compounds were made by modifying this core structure to explore the pharmacophore.
View Article and Find Full Text PDFNat Geosci
December 2024
Université Paris Cité, Institut de Physique du Globe de Paris, CNRS, Paris, France.
Saturn's rings have been estimated to be as young as about 100 to 400 million years old according to the hypothesis that non-icy micrometeoroid bombardment acts to darken the rings over time and the Cassini observation indicated that the ring particles appear to be relatively clean. These young age estimates assume that the rings formed out of pure water ice particles with a high accretion efficiency of impacting non-icy micrometeoroid material ( ≳ 10%). Here we show, using numerical simulations of hypervelocity micrometeoroid impacts on a ring particle, that non-icy material may not be as readily accreted as previously thought.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Laboratory of Synthesis and Natural Products (LSPN), Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, CH-1015 Lausanne, Switzerland.
In the dyotropic rearrangement of molecules with semiflexible structures, characterized by a freely rotating static C-C bond, the formation of a mixture of products is common due to the coexistence of several energetically comparable conformers. Herein, we report that it is possible to modulate the shifting groups by adjusting the metal's coordination sphere in Pd-based dyotropic rearrangement. In the presence of a catalytic amount of Pd(II) salt, the reaction of γ-hydroxyalkenes or γ,δ-dihydroxyalkenes with Selectfluor affords fluorinated tetrahydropyranols or 6,8-dioxabicyclo[3.
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