The wide use of copper is limited by its rapid oxidation. Main oxidation mitigation approaches involve alloying or surface passivation technologies. However, surface alloying often modifies the physical properties of copper, while surface passivation is characterized by limited thermal and chemical stability. Herein, we demonstrate an electrochemical approach for surface-anchoring of an N-heterocyclic carbene (NHC) nanolayer on a copper electrode by electro-deposition of alkyne-functionalized imidazolium cations. Water reduction reaction generated a high concentration of hydroxide ions that induced deprotonation of imidazolium cations and self-assembly of NHCs on the copper electrode. In addition, alkyne group deprotonation enabled on-surface polymerization by coupling surface-anchored and solvated NHCs, which resulted in a 2 nm thick NHC-nanolayer. Copper film coated with a NHC-nanolayer demonstrated high oxidation resistance at elevated temperatures and under alkaline conditions.
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http://dx.doi.org/10.1002/anie.202201093 | DOI Listing |
Chem Asian J
January 2025
Technische Universität Braunschweig, Institute of Medicinal and Pharmaceutical Chemistry, Beethovenstr. 55, 38106, Braunschweig, GERMANY.
Silver N-heterocyclic carbene (NHC) complexes are known to form biscarbene species from monocarbene analogs in protic polar solvents. However, the effect of the respective species of silver NHC complexes on their biological activity against bacteria or cancer cells has not been systematically explored, either in vitro or in vivo. The direct and simple conversion of monocarbene silver N-heterocyclic carbene (NHC) halide complexes (NHC)AgX, (X= Cl, Br) 1a/b - 5a/b to their biscarbene analogues (NHC)2AgX 1c/d - 5c/d is reported.
View Article and Find Full Text PDFChem Biol Interact
January 2025
Institute of Vascular Biology and Thrombosis Research, Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria. Electronic address:
A series of eight gold(I) N-heterocyclic carbene (NHC) complexes [Au(IMes)(HLn)] based on 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes) and 7-azaindole derivatives (HLn), where n = 1-8 for HL1 = 5-flouro-7-azaindole, HL2 = 5-bromo-7-azaindole, HL3 = 3-chloro-7-azaindole, HL4 = 3-iodo-7-azaindole, HL5 = 5-bromo-3-chloro-7-azaindole, HL6 = 5-bromo-3-iodo-7-azaindole, HL7 = 4-chloro-2-methyl-7-azaindole and HL8 = 7-azaindole, was prepared, characterised and studied for their in vitro anti-cancer and anti-inflammatory effects. The complexes showed significant cytotoxicity on human ovarian cancer cell lines (A2780, IC ≈ 8-19 μM and A2780R, IC ≈ 8-19 μM) and lowered toxicity in normal HaCat and MRC-5 cells. Cellular effects of the selected complexes 1 and 7 were evaluated in A2780 cells using flow cytometry.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
CNRS/UCSD, Chemistry, University of California, San Diego, 5213 Pacific Hall,, Department of Chemistry, 92093-0343, La jolla, UNITED STATES.
N-Heterocyclic carbene (NHC) ligands possess the ability to stabilize metal-based nanomaterials for a broad range of applications. With respect to metal-hydride nanomaterials, however, carbenes are rare, which is surprising if one considers the importance of metal-hydride bonds across the chemical sciences. In this study, we introduce a bottom-up approach leveraging preexisting metal-metal m-center-n-electron (mc-ne) bonds to access a highly stable cyclic(alkyl)amino carbene (CAAC) copper-hydride nanocluster, [(CAAC)6Cu14H12][OTf]2 with superior stability compared to Stryker's reagent, a popular commercial phosphine-based copper hydride catalyst.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Department for Chemistry, Technical University of Denmark (DTU), 2800 Kongens Lyngby, Denmark.
A new Ru(II) complex featuring a novel amino-di(N-heterocyclic carbene) CNC pincer ligand, CNC-RuCl(CO) (Ru-1), has been developed and characterised in depth. Ru-1 forms an efficient and durable catalytic formic acid dehydrogenation system in combination with the ionic liquid 1-ethyl-3-methylimidazolium diethylphosphate (EMIM PO(OEt)).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Freie Universitat Berlin, Chemistry and Biochemistry, Fabeckstraße 34-36, 14195, Berlin, GERMANY.
Neutral mesoionic carbenes (MICs) based on a 1,2,3-triazole core have had a strong impact on various branches of chemistry such as homogeneous catalysis, electrocatalysis, and photochemistry/photophysics. We present here the first general synthesis of anionic mesoionic carbenes (anMICs) based on a 1,2,3-triazole core and a borate backbone. The free anMIC is stable in solution under an inert atmosphere at low temperatures, and can be stored for several weeks.
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