Gold Nanoparticles Supported on Mesoporous Titania Thin Films with High Loading as a CO Oxidation Catalyst

In the present work, 2.4 nm gold nanoparticles (Au NPs) are uniformly dispersed on mesoporous titania thin films which are structurally tuned by controlling the calcination temperature. The gold content of the catalyst is as high as 27.8 wt %. To our knowledge, such a high loading of Au NPs with good dispersity has not been reported until now. Furthermore, the reaction rate of the gold particles is enhanced by one order of magnitude when supported on mesoporous titania compared to non‐porous titania. This significant improvement can be explained by an increase in the diffusivity of the substrate due to the presence of mesopores, the resistance to agglomeration, and improved oxygen activation.     

Tetralactam-modified gold electrodes for amperometric detection of acrylic acid

The presence of toxic acrylamide in a wide range of food products such as potato crisps, French fries or bread has been confirmed by Swedish scientists from Stockholm University. The neurotoxicity and possible carcinogenicity of this compound and its metabolites compel us to control them by quantitative and qualitative assays. Exposing acrylamide to pH extremes results in its hydrolysis to acrylic acid or its salt. In this work, we present the use of gold electrodes coated with self-assembled monolayers (SAMs) containing tetralactam molecules and its precursor as active elements for voltammetric detection of acrylic acid in water solution. The host molecules have been immobilised on the electrode surface by covalent Au–S bond or by embedment method into the thiol layer via hydrophobic and van der Waals interactions. Interactions with analytes were confirmed by Osteryoung square-wave voltammetry.     

Multifunctional triazolylferrocenyl Janus dendron: Nanoparticle stabilizer,smart drug carrier and supramolecular nanoreactor

Owing to their unique broken symmetry, amphiphilic Janus dendrimers and dendons provide fascinating properties for material, biological, pharmaceutical and biomedical applications. The integration of various organometallic moieties into these macromolecules will further offer the opportunity to form complex and intelligent architectures and materials. Here, we report a novel, simple and multifunctional Janus dendron containing redox‐reversible hydrophobic ferrocene (Fc) unit, complexing‐effective 1,2,3‐triazole ligand and biocompatible hydrophilic triethylene glycol termini. Silver and gold nanoparticles were firstly successfully prepared by using the Janus dendron as the reducing agent of Au(III) and Ag(I), and the stabilizer of the corresponding nanoparticles. The redox response of the Fc moiety was then employed to trigger the release of model drug, rhodamine B, encapsulated in supramolecular micelles formed by the self‐assembly of the Janus dendron. Finally, the precise and excellent metal‐complexing ability of the triazole group in this dendron was fully utilized to stabilize a water‐soluble Cu(I) catalyst, forming supramolecular nanoreactors for the catalysis of the copper(I)‐catalyzed azide alkyne cycloaddition click reaction in only water. The multifunctional characteristics of this dendron highlight the potential for organometallic Janus dendrimers and dendrons in the fields of functional materials and nanomedicines.     

Alkyne Difunctionalization by Dual Gold/Photoredox Catalysis

Highly selective tandem nucleophilic addition/cross‐coupling reactions of alkynes have been developed using visible‐light‐promoted dual gold/photoredox catalysis. The simultaneous oxidation of Au^I and coordination of the coupling partner by photo‐generated aryl radicals, and the use of catalytically inactive gold precatalysts allows for high levels of selectivity for the cross‐coupled products without competing hydrofunctionalization or homocoupling. As demonstrated in representative arylative Meyer–Schuster and hydration reactions, this work expands the scope of dual gold/photoredox catalysis to the largest class of substrates for gold catalysts and benefits from the mild and environmentally attractive nature of visible‐light activation.