Gold-catalyzed thioetherification of allyl, benzyl, and propargyl phosphates

2022 ◽  
Author(s):  
Hiroki Miura ◽  
Tomoya Toyomasu ◽  
Hidenori Nishio ◽  
Tetsuya Shishido
Keyword(s):  
Gold Nanoparticles ◽  
Reaction Conditions

Gold-catalyzed thioetherification of C(sp3)–O bonds is described. The reaction of allyl phosphates and thiosilanes in the presence of gold nanoparticles supported on ZrO2 proceeded efficiently under mild reaction conditions to...

Preparation of the Gold Nanoparticles and its Activity for Single-Step Amination of Benzene to Aniline

2013 ◽  
Vol 661 ◽  
pp. 47-52
Author(s):  
Gang Chen ◽  
Chun Hua Yang
Keyword(s):  
Gold Nanoparticles ◽  
Single Step ◽  
Xps Analysis ◽  
Deposition Method ◽  
Reaction Conditions ◽  
Catalyst Amount ◽  
Mild Conditions ◽  
Colloidal Deposition ◽  
Alumina Particles

Gold nanoparticles (AuNPs) were attached to the surface of alumina particles by an in-situ immobilizing method. SEM and XPS analysis showed that the coverage of alumina particles by AuNPs increased as the amount of alumina decreased; AuNPs onto alumina particles by the conventional colloidal deposition method were also prepared, whose TEM showed that the coverage of AuNPs was evidently smaller than that in the case of modified colloidal deposition method，although the AuNPs were spread almost uniformly over the surface of alumina particles. Au-immobilized alumina particles were subsequently utilized as the catalysts for direct amination of benzene with NH3H2O as an aminating agent and H2O2 as an oxidant under mild conditions. The reaction conditions were optimized: when catalyst amount was 2.0 g, reaction temperature was 50 °C, NH3H2O amount was 60 mL, H2O2 amount was 30 mL, and reaction time is 2 h, Au-immobilized alumina particles showed the highest aniline yield (1.96 mg) for 25 mL benzene.

DNA-Templated Gold Nanoparticles Formation

2008 ◽  
Vol 8 (9) ◽  
pp. 4415-4423 ◽  
Author(s):  
Lanlan Sun ◽  
Yonghai Song ◽  
Li Wang ◽  
Yujing Sun ◽  
Cunlan Guo ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Reaction Time ◽  
Absorption Spectra ◽  
Reaction Temperature ◽  
Intermediate Product ◽  
Gold Nanostructures ◽  
Hybrid Nanoparticles ◽  
Reaction Conditions ◽  
Xps Spectra ◽  
Dna Concentration

The interaction between HAuCl4 and DNA has enabled creation of DNA-templated gold nanoparticles without formation of large nanoparticles. It was found that spheral DNA-HAuCl4 hybrid of 8.7nm in diameter, flower-like DNA-HAuCl4 hybrid, nanoparticles chains and nanoparticles network of DNA-HAuCl4 hybrid could be obtained by varying the reaction conditions, including DNA concentration and reaction temperature. The intermediate product was investigated by shortening the reaction time of DNA and HAuCl4, and the obtained nanoparticles preserved a small DNA segment, which indicated that the reaction between DNA and HAuCl4 had a process. The addition of reduction reagent resulted in DNA-templated gold nanoparticles and nanoflowers, respectively. UV-vis absorption spectra were used to characterize the DNA-HAuCl4 hybrid and the gold nanostructures templated on DNA, and XPS spectra were used to compare the composition of DNA-Au(III) complex and gold nanoparticles. AFM and TEM results revealed that the spheral gold nanoparticles of about 11 nm in size and flower-like gold nanoparticles were formed after the addition of NaBH4.

scholarly journals Optimisation and Scale-up of the Synthesis of Gold Nanoparticle-Wool Fibre Composites

2021 ◽  
Author(s):  
◽  
Thomas Wade Nilsson
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Laboratory Scale ◽  
Metal Nanoparticle ◽  
Ex Situ ◽  
Wool Fibre ◽  
Reaction Conditions ◽  
Gold Colloids ◽  
Fibre Composites

<p>Gold nanoparticles are known for their remarkable optical properties; they exhibit localised surface plasmon resonance bands in the visible region of the electromagnetic spectrum. This has led to their use as luxury dyes for the colouring of wool fibres. Gold is associated with wealth and desire, and as such, gold nanoparticle-wool fibre composites may be fabricated into high-quality garments, apparel, textiles and carpets for international markets.  Novel proprietary approaches for the laboratory-scale synthesis of gold nanoparticle-wool fibre composites have previously been developed by Professor James Johnston and Dr Kerstin Lucas. The innovative nanotechnology utilises the affinity of gold for sulfur-containing cystine residues in wool fibres, to attract and bind the gold nanoparticles. One approach involves the absorption of gold ions by wool fibres and the nucleation of gold nanoparticles in-situ. In an alternative method, gold nanoparticle colloids are synthesised ex-situ, and are then used to colour wool fibres.  The reaction conditions of the in-situ and ex-situ approaches were optimised with respect to cost-effectiveness and scalability. The gold content of the in-situ composites was minimised, and the range of possible colours widened, via the use of heat and external reducing agents. In the ex-situ process, the formation and stability of the gold nanoparticle colloids was studied, and the reaction conditions of the synthesis were optimised. The rate of uptake of gold nanoparticles to wool was controlled by manipulating the pH, concentration, volume, and wool to liquor ratio of the gold colloids, and by introducing auxiliary agents into the dyeing reactions. A range of chemical treatments and alternative stabilising agents were investigated to improve the washfastness properties of ex-situ gold nanoparticle-wool fibre composites.  There are numerous size-controllable syntheses of gold nanoparticle colloids at the laboratory-scale. However, when the process is scaled-up, gold nanoparticle synthesis is no longer trivial. A barrel reactor with a high velocity mixer was utilised to achieve uniform mixing and heating in the synthesis of gold nanoparticle colloids of up to 90 L in volume. The ratios of gold to stabilising agents in the colloidal gold syntheses were optimised to result in more stable and reproducible gold colloids for subsequent dyeing reactions.  The uniform colouring of small quantities of wool is easily achieved in the laboratory, but preventing colour variation across a kilogram of wool is a significant challenge. Initial kilogram-scale dyeing reactions in static tank reactors resulted in unevenly coloured gold nanoparticle-wool fibre composites. To overcome this, conventional hank dyeing equipment was used to colour felted merino yarn, in collaboration with the wool dyeing industry. Modified hank dyeing procedures were recreated in the laboratory, and composites with remarkable colour uniformity were produced. Industrial package dyeing reactors were then used to colour fine merino yarn with gold nanoparticle colloids. The uptake of gold nanoparticles was controlled by manipulating the owrates, ow direction and amounts of auxiliary agents that were employed in the dyeing reactions.  Based upon the success of the industrial dyeing reactions, novel dyeing reactors were developed for the colouring of hanks of wool fibres and yarns in the laboratory. These reactors utilised rapid dye circulation and pressure to produce gold nanoparticle-wool fibre composites with remarkable colour uniformity. The composites were used to fabricate luxury apparel and carpets for international trade expositions.  The pathway from synthesis in the laboratory to pilot-scale production of gold nanoparticle-wool fibre composites is presented. The PhD research was an integral step in the successful commercialisation of this innovative nanotechnology, and will assist in scaling-up the synthesis of metal nanoparticle colloids and nanocomposites in the future.</p>

scholarly journals Study on the antioxidant cosmetic preparation from Spirulinaplatensis and gold nanoparticles

2015 ◽  
Vol 18 (2) ◽  
pp. 36-45
Author(s):  
Lan Thi My Nguyen ◽  
Quyen Thi Hoang Nguyen ◽  
Tham Thi Mong Doan ◽  
Loan Thi Thanh Le ◽  
Hieu Trung Tran ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Gold Nanoparticles ◽  
Vitamin C ◽  
Premature Aging ◽  
Reaction Conditions ◽  
Skin Rejuvenation ◽  
Skin Cells ◽  
Diammonium Salt ◽  
Potential Applications ◽  
Main Components

Oxidation can generate free radicals which damage important molecules including lipids, proteins, and nucleic acid, and causes premature aging. The oxidation of skin cells manifests as wrinkles, freckles and many other serious symptoms. To develop natural products with high antioxidant ability for skin care, we developed mixtures of Spirulina platensis biomass, gold nanoparticles (AuNP: 10 nm) and vitamin C at different ratios. The antioxidant activity of the mixtures was measured by ABTS (2,2′-azino-bis (3- ethylbenzothiazoline-6-sulfonic acid) diammonium salt) assay. The mixture of S. platensis (1000 ppm), AuNP (10 ppm), and vitamin C (10 ppm) showed excellent antioxidant activity with 95 % efficiency after 30 minutes and 100 % efficiency after 120 minutes under the reaction conditions. The combination of the mixture and the polyvinylpyrrolidone (PVP) binder was sterilized by gamma Co-60 radiation. The sterilization dose of 16 kGy was selected due to theabsence of aerobic microorganisms in the antioxidant cosmetic preparation. Thus, the cosmetic preparation in paste form containing three main components of S. platensis, gold nanoparticles, and vitamin C combinated with PVP binder has a potential applications in the field of cosmetics, especially for facial skin rejuvenation.

Characterization of phospholipid-encapsulated gold nanoparticles: a versatile platform to study drug delivery and cellular uptake mechanisms

2015 ◽  
Vol 93 (2) ◽  
pp. 265-271 ◽  
Author(s):  
Meijing Wang ◽  
Nils O. Petersen
Keyword(s):  
Drug Delivery ◽  
Gold Nanoparticles ◽  
Cellular Uptake ◽  
Study Drug ◽  
Cellular Systems ◽  
Reaction Conditions ◽  
Overall Stability ◽  
Comprehensive Characterization ◽  
Uptake Mechanisms

The data presented in this work aim to provide a comprehensive characterization of lipid-coated gold nanoparticles. We show that it is possible to envelop gold nanoparticles with a coating of lipids during the formation of the gold nanoparticles, that the gold in these lipid-coated gold nanoparticles is crystalline and the size and shape can be controlled by the reaction conditions (within limits), that the lipid coating corresponds to a thickness consistent with the formation of a bilayer, that the bilayer can include fluorescent probes that, while quenched, can be used to trace the fate of the gold nanoparticles in cellular systems, that their surface charge, and hence their overall stability in solution, is influenced by the lipid coating, and that while some lipid dyes may exchange among the particles, they are sufficiently stable to exchange to permit their use as tracers in cell studies. We believe this is the most comprehensive characterization of these systems to date.

scholarly journals Impact of Specifically Adsorbing Anions on the Electroless Growth of Gold Nanotubes

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Falk Muench ◽  
Cornelia Neetzel ◽  
Stefan Lauterbach ◽  
Hans-Joachim Kleebe ◽  
Wolfgang Ensinger
Keyword(s):  
Thin Films ◽  
Gold Nanoparticles ◽  
Reaction Rate ◽  
Porous Structures ◽  
Gold Plating ◽  
Reaction Conditions ◽  
Aspect Ratios ◽  
Polymer Templates ◽  
Metal Nanotubes ◽  
Enhanced Stability

Electroless metal deposition on nanochannel-containing templates is a versatile route towards metal nanotubes and nanowires if the plating reaction can be sufficiently controlled. In this study, disulfitoaurate-formaldehyde-based gold plating baths were modified by the addition of halides, pseudohalides, and EDTA. The introduction of specifically adsorbing anions strongly affected the heterogeneously autocatalyzed plating reaction and allowed the regulation of the reaction rate and the product morphology. The new plating baths showed enhanced stability and allowed the synthesis of homogeneous nanotubes of high aspect ratios (>150) in 30 μm thick ion track-etched polymer templates. Depending on the reaction conditions, solid and porous structures consisting of gold nanoparticles of differing size and shape were accessible. The presented strategy offers adapted gold thin films, nanotubes, and nanowires for applications in catalysis or sensing.

scholarly journals Seed-Mediated Electroless Deposition of Gold Nanoparticles for Highly Uniform and Efficient SERS Enhancement

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 185 ◽  
Author(s):  
Junqi Tang ◽  
Quanhong Ou ◽  
Haichun Zhou ◽  
Limin Qi ◽  
Shiqing Man
Keyword(s):  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Electroless Deposition ◽  
Trisodium Citrate ◽  
Mixed Solution ◽  
Large Area ◽  
Reaction Conditions ◽  
Au Nps ◽  
Sers Enhancement ◽  
Seed Mediated

A seed-mediated electroless deposition (SMED) approach for fabrication of large-area and uniform gold nanoparticle films as efficient and reproducible as surface-enhanced Raman scattering (SERS) substrates was presented. This approach involved a seeding pretreatment procedure and a subsequent growth step. The former referred to activation of polylysine-coated glass slides in gold seed solution, and the latter required a careful control of the reactant concentration and reaction time. With the aid of gold seeds and appropriate reaction conditions, a large-area and uniform nanofilm with evenly distributed gold nanoparticles (Au NPs) was formed on the surface of the substrates after adding a mixed solution containing ascorbic acid and trisodium citrate. The morphology of the Au nanofilm was examined by scanning electron microscopy. The size evolution of Au NPs on the surface of the substrates was analyzed in detail. The nanofilm substrate was prepared by reaction conditions of the seeded activation process: 10 mL ascorbic acid and trisodium citrate mixture and 30 min of soaking time, which exhibited an excellent uniformity and reproducibility of SERS enhancement with relative standard deviation (RSD) values of less than 8% (particularly, a RSD value of 3% can be reached for the optimized measurement). Compared to the common electroless deposition, the seed-mediated electroless deposition possessed inherent advantages in controllability, reproducibility, and economic benefit.

scholarly journals Fourier Analysis of Deformations of Catalytic Gold Nanoparticles under Reaction Conditions

2010 ◽  
Vol 16 (S2) ◽  
pp. 1816-1817
Author(s):  
T Kawasaki ◽  
T Miura ◽  
T Tanji
Keyword(s):  
Gold Nanoparticles ◽  
Fourier Analysis ◽  
Reaction Conditions

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

scholarly journals Selective Synthesis of Benzimidazoles from o-Phenylenediamine and Aldehydes Promoted by Supported Gold Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2405
Author(s):  
Marina A. Tzani ◽  
Catherine Gabriel ◽  
Ioannis N. Lykakis
Keyword(s):  
Gold Nanoparticles ◽  
Significant Loss ◽  
Efficient Synthesis ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
Heterocyclic Molecules ◽  
Selective Reaction ◽  
High Yields ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

We investigated the catalytic efficacy of supported gold nanoparticles (AuNPs) towards the selective reaction between o-phenylenediamine and aldehydes that yields 2-substituted benzimidazoles. Among several supported gold nanoparticle platforms, the Au/TiO2 provides a series of 2-aryl and 2-alkyl substituted benzimidazoles at ambient conditions, in the absence of additives and in high yields, using the mixture CHCl3:MeOH in ratio 3:1 as the reaction solvent. Among the AuNPs catalysts used herein, the Au/TiO2 containing small-size nanoparticles is found to be the most active towards the present catalytic methodology. The Au/TiO2 can be recovered and reused at least five times without a significant loss of its catalytic efficacy. The present catalytic synthetic protocol applies to a broad substrate scope and represents an efficient method for the formation of a C–N bond under mild reaction conditions. Notably, this catalytic methodology provides the regio-isomer of the anthelmintic drug, Thiabendazole, in a lab-scale showing its applicability in the efficient synthesis of such N-heterocyclic molecules at industrial levels.

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