Dataset Information

Reduction of the Diazo Functionality of ?-Diazocarbonyl Compounds into a Methylene Group by NH₃BH₃ or NaBH₄ Catalyzed by Au Nanoparticles.

ABSTRACT: Supported Au nanoparticles on TiO₂ (1 mol%) are capable of catalyzing the reduction of the carbene-like diazo functionality of ?-diazocarbonyl compounds into a methylene group [C=(N₂) ? CH₂] by NH₃BH₃ or NaBH₄ in methanol as solvent. The Au-catalyzed reduction that occurs within a few minutes at room temperature formally requires one hydride equivalent (B-H) and one proton that originates from the protic solvent. This pathway is in contrast to the Pt/CeO₂-catalyzed reaction of ?-diazocarbonyl compounds with NH₃BH₃ in methanol, which leads to the corresponding hydrazones instead. Under our stoichiometric Au-catalyzed reaction conditions, the ketone-type carbonyls remain intact, which is in contrast to the uncatalyzed conditions where they are selectively reduced by the boron hydride reagent. It is proposed that the transformation occurs via the formation of chemisorbed carbenes on Au nanoparticles, having proximally activated the boron hydride reagent. This protocol is the first general example of catalytic transfer hydrogenation of the carbene-like ? -ketodiazo functionality.

SUBMITTER: Kidonakis M

PROVIDER: S-EPMC7832297 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Reduction of the Diazo Functionality of α-Diazocarbonyl Compounds into a Methylene Group by NH3BH3 or NaBH4 Catalyzed by Au Nanoparticles.

Kidonakis Marios M Stratakis Manolis M

Nanomaterials (Basel, Switzerland) 20210118 1

Supported Au nanoparticles on TiO2 (1 mol%) are capable of catalyzing the reduction of the carbene-like diazo functionality of α-diazocarbonyl compounds into a methylene group [C=(N2) → CH2] by NH3BH3 or NaBH4 in methanol as solvent. The Au-catalyzed reduction that occurs within a few minutes at room temperature formally requires one hydride equivalent (B-H) and one proton that originates from the protic solvent. This pathway is i ...[more]

PMID: 33477732

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Project description:BackgroundBiofilm formation on medical device surfaces is a persistent problem that shelters bacteria and encourages infections and implant rejection. One promising approach to tackle this problem is to coat the medical device with an antimicrobial material. In this work, for the first time, we impart antimicrobial functionality to Ti3Au intermetallic alloy thin film coatings, while maintaining their superior mechanical hardness and biocompatibility.MethodsA mosaic Ti sputtering target is developed to dope controlled amounts of antimicrobial elements of Ag and Cu into a Ti3Au coating matrix by precise control of individual target power levels. The resulting Ti3Au-Ag/Cu thin film coatings are then systematically characterised for their structural, chemical, morphological, mechanical, corrosion, biocompatibility-cytotoxicity and antimicrobial properties.ResultsX-ray diffraction patterns reveal the formation of a super hard β-Ti3Au phase, but the thin films undergo a transition in crystal orientation from (200) to (211) with increasing Ag concentration, whereas introduction of Cu brings no observable changes in crystal orientation. Scanning and transmission electron microscopy analysis show the polyhedral shape of the Ti3Au crystal but agglomeration of Ag particles between crystal grains begins at 1.2 at% Ag and develops into large granules with increasing Ag concentration up to 4.1 at%. The smallest doping concentration of 0.2 at% Ag raises the hardness of the thin film to 14.7 GPa, a 360% improvement compared to the ∼4 GPa hardness of the standard Ti6Al4V base alloy. On the other hand, addition of Cu brings a 315-330% improvement in mechanical hardness of films throughout the entire concentration range of 0.5-7.1 at%. The thin films also show good electrochemical corrosion resistance and a > tenfold reduction in wear rate compared to Ti6Al4V alloy. All thin film samples exhibit very safe cytotoxic profiles towards L929 mouse fibroblast cells when analysed with Alamar blue assay, with ion leaching concentrations lower than 0.2 ppm for Ag and 0.08 ppm for Cu and conductivity tests reveal the positive effect of increased conductivity on myogenic differentiation. Antimicrobial tests show a drastic reduction in microbial survival over a short test period of < 20 min for Ti3Au films doped with Ag or Cu concentrations as low as 0.2-0.5 at%.ConclusionTherefore, according to these results, this work presents a new antimicrobial Ti3Au-Ag/Cu coating material with excellent mechanical performance with the potential to develop wear resistant medical implant devices with resistance to biofilm formation and bacterial infection.

Dataset Information

Reduction of the Diazo Functionality of ?-Diazocarbonyl Compounds into a Methylene Group by NH₃BH₃ or NaBH₄ Catalyzed by Au Nanoparticles.

Publications

Reduction of the Diazo Functionality of α-Diazocarbonyl Compounds into a Methylene Group by NH<sub>3</sub>BH<sub>3</sub> or NaBH<sub>4</sub> Catalyzed by Au Nanoparticles.

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Dataset Information

Reduction of the Diazo Functionality of ?-Diazocarbonyl Compounds into a Methylene Group by NH3BH3 or NaBH4 Catalyzed by Au Nanoparticles.

Publications

Reduction of the Diazo Functionality of α-Diazocarbonyl Compounds into a Methylene Group by NH<sub>3</sub>BH<sub>3</sub> or NaBH<sub>4</sub> Catalyzed by Au Nanoparticles.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Reduction of the Diazo Functionality of ?-Diazocarbonyl Compounds into a Methylene Group by NH₃BH₃ or NaBH₄ Catalyzed by Au Nanoparticles.