Fast One-Step Synthesis of Anisotropic Silver Nanoparticles

The shape control of metal nanoparticles, along with the size, is critical for most of their applications as they control their optical properties. Anisotropic metal nanoparticles show superior performance in a number of applications compared to spherical ones. Shape control is usually achieved by a two-step process, where the first involves the formation of spherical nanoparticles and the second is about the actual shape transformation. In this paper, we report on a fast and facile synthesis of silver nanoplates in a single step, involving laser ablation of a silver target in a liquid medium while this is exposed to light irradiation and hydrogen peroxide flow. We obtained anisotropic particles with a mixture of shapes, of 70–80 nm in size and 10–20 nm in thickness, which showed a plasmon sensitivity greater than 200 nm/RIU.

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One-Step Microwave-Assisted Aqueous Synthesis of Silver-Based Nanoparticles Functionalized by Glutathione

MRS Proceedings ◽

10.1557/opl.2014.865 ◽

2014 ◽

Vol 1675 ◽

pp. 163-168

Author(s):

Myrna Reyes Blas ◽

Maricely Ramírez-Hernandez ◽

Danielle Rentas ◽

Oscar Perales-Perez ◽

Felix R. Román

Keyword(s):

Metal Nanoparticles ◽

Single Step ◽

Food Preservation ◽

Molar Ratio ◽

Aqueous Synthesis ◽

Low Temperature Storage ◽

Microwave Assisted ◽

Food Borne ◽

Transmission Electron ◽

One Step

ABSTRACTThe use of nano-sized silver and its alloys represents an interesting alternative to common food preservation methods, which are based on radiation, heat treatment and low temperature storage. These metal nanoparticles, embedded within a polymeric matrix for instance, would extend the shelf life of perishable foods while acting as a bactericidal agent to prevent food-borne illnesses. Common methods used in the synthesis of metal nanoparticles require toxic solvents and reagents that could be harmful to health and the food itself. In addition, several steps are required to obtain aqueous stable, i.e. dispersible, silver nanoparticles. In this work we propose the microwave-assisted aqueous synthesis of silver-based nanoparticles, (Ag Based NP) functionalized by glutathione (GSH) in a single-step using sodium sulfite (Na2SO3), as reducing agent. Ag-Based nanoparticles were synthesized at pH 6 and 1:3:1 (AgNO3/GSH/ Na2SO3) molar ratio. UV-Vis measurement clearly showed the plasmon peak attributed to silver-based nanoparticles (374 nm). Highly monodispersed water stable Ag-based nanoparticles were observed and 3.897 ± 0.167 nm particle size was determined through Transmission Electron Microscopy. FT-IR measurements suggested the actual GSH-Ag based surface interaction through –SH and –COOH groups; the functionalization by GSH explained the high stability of the nanoparticles in aqueous suspensions. These Ag-GSH nanoparticles exhibited remarkable antimicrobial activity against E. Coli.

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Synthesis of Polycycles and Oxacycles by Tandem Metathesis of endo–norbornene Derivatives

Synthesis ◽

10.1055/a-1348-4242 ◽

2021 ◽

Author(s):

Sambasivarao Kotha ◽

Sunil Pulletikurti ◽

Ambareen Fatma ◽

gopal dhangar ◽

gonna somu Naidu

Keyword(s):

Natural Products ◽

Metal Complex ◽

Carbonyl Group ◽

Single Step ◽

Time Dependent ◽

Computational Studies ◽

Nmr Studies ◽

Tricyclic Compounds ◽

One Step ◽

Norbornene Derivatives

Here, we have demonstrated that the presence of a carbonyl group at C7 position is preventing the olefin metathesis of endo-norbornene derivatives due to the complexation of the metal alkylidene. Time-dependent NMR studies showed the presence of new proton signals in the metal alkylidene region, which indicate the formation of metal complex with the carbonyl group of the substrate. These observations were further proved by ESI-MS analysis. Whereas, computational studies provided that the catalyst was interacting with the C7 carbonyl group and aligned perpendicular to that of norbornene olefin. Later, these endo-keto norbornene derivatives were reduced to hydroxyl derivatives diastereoselectively. Ring-rearrangement metathesis (RRM) of these hydroxyl derivatives, produced the [6/5/6], and [5/6/5] carbo-tricyclic cores of the natural products in one step. Whereas the RRM of O-allyl derivatives, delivered the oxa-tricyclic compounds in a single step with excellent yields.

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Single Step 2-Port Device De-Embedding Algorithm for Fixture-DUT-Fixture Network Assembly

Electronics ◽

10.3390/electronics10111275 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1275

Author(s):

Simone Scafati ◽

Enza Pellegrino ◽

Francesco de Paulis ◽

Carlo Olivieri ◽

James Drewniak ◽

...

Keyword(s):

Standard Technique ◽

Single Step ◽

Scattering Parameters ◽

Linear Set ◽

S Parameter ◽

Parameter Conversion ◽

Before And After ◽

One Step ◽

Typical Measurement

The de-embedding of measurement fixtures is relevant for an accurate experimental characterization of radio frequency and digital electronic devices. The standard technique consists in removing the effects of the measurement fixtures by the calculation of the transfer scattering parameters (T-parameters) from the available measured (or simulated) global scattering parameters (S-parameters). The standard de-embedding is achieved by a multiple steps process, involving the S-to-T and subsequent T-to-S parameter conversion. In a typical measurement setup, two fixtures are usually placed before and after the device under test (DUT) allowing the connection of the device to the calibrated vector network analyzer coaxial ports. An alternative method is proposed in this paper: it is based on the newly developed multi-network cascading algorithm. The matrices involved in the fixture-DUT-fixture cascading gives rise to a non-linear set of equations that is in one step analytically solved in closed form, obtaining a unique solution. The method is shown to be effective and at least as accurate as the standard multi-step de-embedding one.

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Computational and experimental investigations of one-step conversion of poly(carbonate)s into value-added poly(aryl ether sulfone)s

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1600924113 ◽

2016 ◽

Vol 113 (28) ◽

pp. 7722-7726 ◽

Cited By ~ 29

Author(s):

Gavin O. Jones ◽

Alexander Yuen ◽

Rudy J. Wojtecki ◽

James L. Hedrick ◽

Jeannette M. García

Keyword(s):

High Performance ◽

Density Functional ◽

Value Added ◽

Single Step ◽

Nucleophilic Attack ◽

Experimental Investigations ◽

Aryl Ether ◽

One Step ◽

Poly Carbonate

It is estimated that ∼2.7 million tons poly(carbonate)s (PCs) are produced annually worldwide. In 2008, retailers pulled products from store shelves after reports of bisphenol A (BPA) leaching from baby bottles, reusable drink bottles, and other retail products. Since PCs are not typically recycled, a need for the repurposing of the PC waste has arisen. We report the one-step synthesis of poly(aryl ether sulfone)s (PSUs) from the depolymerization of PCs and in situ polycondensation with bis(aryl fluorides) in the presence of carbonate salts. PSUs are high-performance engineering thermoplastics that are commonly used for reverse osmosis and water purification membranes, medical equipment, as well as high temperature applications. PSUs generated through this cascade approach were isolated in high purity and yield with the expected thermal properties and represent a procedure for direct conversion of one class of polymer to another in a single step. Computational investigations performed with density functional theory predict that the carbonate salt plays two important catalytic roles in this reaction: it decomposes the PCs by nucleophilic attack, and in the subsequent polyether formation process, it promotes the reaction of phenolate dimers formed in situ with the aryl fluorides present. We envision repurposing poly(BPA carbonate) for the production of value-added polymers.

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On-demand shape transformation of polymer vesicles via site-specific isomerization of hydrazone photoswitches in monodisperse hydrophobic oligomers

Polymer Chemistry ◽

10.1039/d1py00981h ◽

2021 ◽

Author(s):

Valene Wang ◽

Jiwon Kim ◽

Junyoung Kim ◽

Seul Woo Lee ◽

Kyoung Taek Kim

Keyword(s):

Drug Delivery ◽

Block Copolymers ◽

Conformational Change ◽

Self Assembly ◽

Shape Control ◽

Shape Transformation ◽

Site Specific ◽

On Demand ◽

Polymer Vesicles

The shape control of nanostructures formed by the solution self-assembly of block copolymers is of significance for drug delivery. In particular, site-specific perturbation resulting in the conformational change of the...

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An effective GC method for the determination of the fatty acid composition in silkworm pupae oil using a two-step methylation process

Journal of the Serbian Chemical Society ◽

10.2298/jsc140401073w ◽

2015 ◽

Vol 80 (1) ◽

pp. 9-20 ◽

Cited By ~ 15

Author(s):

Jun Wang ◽

Weiwei Wu ◽

Xudong Wang ◽

Min Wang ◽

Fuan Wu

Keyword(s):

Fatty Acid Composition ◽

Fatty Acid ◽

Acid Composition ◽

Methyl Esters ◽

Superior Performance ◽

Step Procedure ◽

Silkworm Pupae ◽

Chromatographic Procedure ◽

One Step ◽

Synthesis Yield

In search of an accurate and effective method to determine fatty acid composition in silkworm pupae oils, five methylation methods were evaluated for use in the gas chromatographic (GC) quantitation of fatty acid methyl esters (FAMEs), including one-step esterification catalyzed by an acidic (H2SO4 and BF3) or alkali catalyst (KOH and NaOCH3) and a two-step procedure catalyzed successively by KOH and H2SO4. These methods were comparatively adopted to quantify FAMEs in silkworm pupae oil using GC-MS and GC and then validate their precision, stability and average recovery rates. The results indicated that compared with the other four methyl esterification methods, two-step methylation effectively improves the synthesis yield of FAMEs, conserves agents, and eliminates the usage of potential harmful reagents. The proposed GC method has been validated, shows good accuracy and precision, and has been applied successfully to the quantification of FAMEs in several varieties of silkworm pupae oils. The short analytical run time leads to low costs and a fast chromatographic procedure. In summary, two-step pretreatment had superior performance, providing technical references for the determination and analysis of fatty acids in other oils.

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A Single-Step Synthesis of Azetidine-3-Amines

10.26434/chemrxiv.12846629.v1 ◽

2020 ◽

Author(s):

Brian J Wang ◽

Matthew Duncton

Keyword(s):

Functional Groups ◽

Late Stage ◽

Single Step ◽

Secondary Amines ◽

High Yield ◽

Primary Amines ◽

Privileged Structure ◽

One Step ◽

Alternative Procedures ◽

Approved Drugs

<div> <p>The azetidine group is frequently encountered within contemporary medicinal chemistry where it is viewed as a privileged structure. However, the introduction of an azetidine can be synthetically challenging. Herein, a straight-forward one step synthesis of azetidine-3-amines, starting from a bench stable, commercial material is presented. The reaction tolerates functional groups commonly encountered in biological-, medicinal- and agro-chemistry, and proceeds in moderate-to-high yield with secondary amines, and moderate-to-low yield with primary amines. The methodology compares favorably to recent alternative procedures and can be utilized in “any-stage” functionalization, including late-stage azetidinylation of approved drugs and other compounds with pharmacological activity.</p> </div>

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Three-component synthesis of highly functionalized aziridines containing a peptide side chain and their one-step transformation into β-functionalized α-ketoamides

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.12.166 ◽

2016 ◽

Vol 12 ◽

pp. 1772-1777 ◽

Cited By ~ 3

Author(s):

Lena Huck ◽

Juan F González ◽

Elena de la Cuesta ◽

J Carlos Menéndez

Keyword(s):

Single Step ◽

Side Chain ◽

One Pot ◽

Aziridine Ring ◽

Component Process ◽

Mild Conditions ◽

One Step

A sequential three-component process is described, starting from 3-arylmethylene-2,5-piperazinediones and involving a one-pot sequence of reactions achieving regioselective opening of the 2,5-diketopiperazine ring and diastereoselective generation of an aziridine ring. This method allows the preparation of N-unprotected, trisubstituted aziridines bearing a peptide side chain under mild conditions. Their transformation into β-trifluoroacetamido-α-ketoamide and α,β-diketoamide frameworks was also achieved in a single step.

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