Name: generation of zerovalent metal core nanoparticles using n-(2-aminoethyl)-3-aminosilanetriol
Uploaded: 2016-02-11T13:00:00.000+00:00
Duration: 8 min 12 s
Description: Watch this Scientific Journal Video about Generation of Zerovalent Metal Core Nanoparticles Using n-2-aminoethyl-3-aminosilanetriol at JoVE.com

Dr. B.P.S. Chauhan would like to gratefully acknowledge William Paterson University for assigned release time (ART) award for part of the research described here and also for the research program in general.

Nota: Todos los reactivos se utilizan como es desde el fabricante sin purificación adicional. Las reacciones fueron controlados durante hasta una semana por medio de espectroscopia UV-Vis para asegurar la reducción completa. Todas las reacciones se llevan a cabo bajo una campana de ventilación y vestimenta de seguridad apropiada es usar en todo momento, incluyendo guantes, gafas protectoras y batas de laboratorio. 1. Síntesis de nanopartículas de plata <ol><li> Pesar 0,0169 g (0,1 mmol) de nitrato de plata directamente en un 50 ml matraz de Erlenmeyer. </li><li> Añadir en 20 ml de 18,2 mO de agua ultrapura y una barra agitadora magnética. Cubra matraz con tapón para evitar la evaporación. </li><li> Colocar el frasco en un baño de aceite situado sobre una placa de agitación / caliente y asegúrese de que la temperatura se mantiene a 60 ° C. </li><li> Añadir lentamente 144 l (0,2 mmol) de 2-AST usando una micropipeta de precisión. pipeta Flush varias veces en solución para asegurar todo el silano se transfiere a la solución. </li><li> Tomar lecturas de espectroscopia UV-Vissegún el protocolo que aparece en la Sección 5. </li><li> Después de 6 horas, retirar la muestra del baño de aceite y transferir a un vial de 20 ml de muestra para almacenamiento, TEM, FTIR y su posterior análisis. Nota: Síntesis de nanopartículas de oro y paladio sigue el mismo método y estequiométricas cantidades con la excepción de nanopartículas de oro que requieren 216 l (0,3 mmol) 2-AST. La reacción puede continuar para producir nanopartículas para un máximo de 2 semanas, pero la tasa no es significativo en comparación con la tasa inicial. </li></ol> 2. microscopio electrónico de transmisión (TEM) Preparación de muestras <ol><li> Asegúrese de que la muestra se haya enfriado hasta la temperatura ambiente. </li><li> Coloque una rejilla de cobre recubierta de Formvar-200-malla de carbono en un pedazo de papel en blanco filtro. </li><li> Usando una pipeta de plástico de 1 ml Pasteur, soltar fundido aproximadamente 60 l de la muestra de nanopartículas directamente sobre la rejilla. </li><li> Deje que la rejilla se seque durante 24 horas antes de exponer. </li><li> Tomar imágenes de TEM de alta resolución con las siguientes condiciones:10 mu actuales y 100 kV de tensión de aceleración 22. </li></ol> 3. Resonancia Magnética Nuclear (RMN) Preparación de la muestra Nota: Realice RMN a temperatura ambiente. A altas temperaturas señales pueden coalescer, que degrada la calidad de los espectros obtenidos. <ol><li> Usando una pipeta de precisión, una pipeta 50 l de dióxido de deuterio (D2O) en un tubo de RMN limpio. </li><li> Con otra pipeta limpia, pipeta de 400 l de muestra de nanopartículas en el mismo tubo de RMN. <ol><li> Como muestras pueden adherirse a las paredes internas del tubo de RMN, añadir lentamente las soluciones en el tubo de RMN. Si la muestra se adhiere, tapar el tubo y agitar la parte superior del tubo para forzar la solución a la parte inferior. </li></ol></li><li> Mezclar la muestra por agitación y repetidamente invirtiendo el tubo de RMN. </li><li> tubo de muestras en el lugar de RMN siguiendo las instrucciones establecidas por el protocolo de RMN proporcionado por el fabricante. Un alza de 1.000 exploraciones pueden ser necesarios para res adecuadosolución en un programa de pulso de RMN de protón 1 H. Nota: Las paredes de los tubos de RMN deben estar limpios. Se recomienda que la pared exterior del tubo se limpia con una microfibra o un paño sin pelusa antes del análisis para mayor claridad espectros. </li><li> Desechar la muestra cuando haya terminado. No devuelva la muestra de solución madre. </li></ol> 4. Fourier Transform Infrared Preparación de la muestra (FTIR) <ol><li> Coloque 2 ml de muestra de nanopartículas en un pequeño recipiente de vidrio. Un vial de vidrio de 3 ml tubo o de 1 dracma funciona bien. </li><li> Secar las muestras al colocar el recipiente de vidrio en un desecador de vacío provista de llave. </li><li> Adjuntar desecador a un aparato de bomba de vacío. El secado de las muestras puede tardar varias horas dependiendo de la fuerza de vacío. Considerar las muestras se secan después no hay líquido visible en el envase. </li><li> Raspe la muestra usando una espátula limpia y recoger los materiales sólidos. </li><li> Coloque el material sólido en ATR-FTIR espectroscopio equipado con un cri ZnSeal láser de diodo. </li><li> Obtener espectros FTIR integración de 32 barridos entre 4,000-500 cm -1 con una resolución espectral de 2,0. Utilizar el fondo de aire 23. </li></ol> 5. UV-Vis Spectroscopy Preparación de la muestra <ol><li> Llevar a cabo la espectroscopía UV-Vis en muestras de nanopartículas que se encuentran en una dilución nueve y cincuenta y nueve de la muestra de nanopartículas de agua de modo que la saturación no se produce en el análisis de espectrómetro. </li><li> Extraer muestras de nanopartículas de UV-Vis mientras que la reacción se ejecuta a intervalos de media hora. </li><li> Usando una pipeta de precisión, eliminar 100 l de material de nanopartículas y colocar en una cubeta de plástico. </li><li> Añadir 1 ml de agua ultrapura a la misma cubeta y se mezcla a fondo por lavado de la pipeta varias veces. </li><li> Record UV-Vis espectro de absorbancia entre 250 a 800 nm. </li><li> Después del análisis, no regrese a la muestra de reacción. Disponer de analito en una manera apropiada. </li></ol>

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No hay conflictos de intereses financieros.

Las sales reportados en este trabajo son las únicas sales que se probaron de ese metal. Como resultado, no se sabe que esta estrategia de reacción trabajaría con todas las sales de los metales, en particular oro. La solubilidad de estas sales en el agua también puede afectar el resultado de la reacción en términos de tiempo de reacción, la morfología y los rendimientos. En todas las reacciones, se añadió el silano a una solución de sal de metal ya disuelto. Vale la pena señalar q...

A medida que la demanda aumenta y las aplicaciones de los nanomateriales de diseño, también lo hacen los diversos métodos de síntesis. Los métodos de &quot;arriba hacia abajo&quot;, como la ablación con láser o grabado químico han sido empleados por su excelente capacidad de control y la capacidad de resolver los materiales de forma fiable hasta el nivel inferior a la micra. Estos métodos se basan en materiales a granel que se procesa en componentes más finos, que normalmente aumentan el coste de producción como el tamaño deseado nanoestructura disminuye. Un método alternativo de síntesis a esto es el enfoque &quot;de abajo hacia arriba&quot;, que controla la síntesis a nivel molecular y se acumula a la nanoestructura deseada. Esto imparte un grado significativo de control en el auto-ensamblaje, la funcionalidad, la pasividad y la estabilidad deseada en la generación de estos materiales nanoestructurados 1. Trabajando desde el nivel molecular, nanocompuestos híbridos pueden ser generados proporcionando los beneficios de ambos materiales dentro de la misma structure. A medida que los nanomateriales se sintetizan a través de la estrategia de abajo hacia arriba, los métodos deben ser empleados para controlar el tamaño de partícula, forma, textura, hidrofobicidad, la porosidad, la carga y funcionalidad 2. En la síntesis de nanopartículas de núcleo de metal, la sal de metal inicial se reduce en un proceso autocatalítico para generar partículas de valencia cero, que a su vez dirigen la nucleación de otra partícula. Esto conduce a la agrupación y la producción de nanopartículas por último 3. En un esfuerzo por controlar el tamaño de las nanopartículas creadas y evitar que precipite fuera de la solución, estabilizadores tales como ligandos, agentes tensioactivos, carga iónica, y polímeros grandes son explotados por su capacidad para bloquear las nanopartículas de aglomeración adicional 4-10. Estos materiales inhiben la atracción de van der Waals de las nanopartículas, ya sea a través de impedimento estérico debido a la presencia de grupos voluminosos o mediante repulsiones Coulombic 3. en tsu trabajo, un solo recipiente, la estrategia Facile, sintético para la generación de diversas nanopartículas del núcleo de metal utilizando el silano, N- (2-aminoetil) -3-aminosilanetriol (2-AST) se presenta (Figura 1). Los ligandos de este compuesto son capaces de reducir los precursores de metales y la estabilización de las nanopartículas de metal con una relativamente alta eficacia. Los tres restos silanol presentes también son capaces de reticulación y esto forma una red interconectada de polímero de organosilano impregnada con nanopartículas dentro de su matriz (Figura 2). A diferencia de la mayoría de los silanos, que experimentan fácilmente hidrólisis en presencia de agua, este compuesto se estabiliza en el agua, lo cual es beneficioso para los propósitos de hidrofobicidad, estabilidad y control.

<table><tbody><tr><td>n-(2-aminoethyl)-3-aminosilanetriol (2-AST)</td><td>Gelest</td><td>SIA0590.0</td><td>25% in H&lt;sub&gt;2&lt;/sub&gt;O</td></tr><tr><td>Silver nitrate</td><td>Sigma Aldrich</td><td>S6506</td><td></td></tr><tr><td>Gold(III) chloride trihydrate</td><td>Sigma Aldrich</td><td>520918</td><td></td></tr><tr><td>Palladium(II) Nitrate</td><td>Alfa Aesar</td><td>11035</td><td></td></tr><tr><td>Deuterium Dioxide</td><td>Cambridge Isotope Laboratories</td><td>DLM-4-100</td><td></td></tr></tbody></table>

generation of zerovalent metal core nanoparticles using n-(2-aminoethyl)-3-aminosilanetriol

In this work, a facile one-pot reaction for the formation of metal nanoparticles in a water solution through the use of n-(2-aminoethyl)-3-aminosilanetriol is presented. This compound can be used to effectively reduce and complex metal salts into metal core nanoparticles coated with the compound. By controlling the concentrations of salt and silane one is able to control reaction rates, particle size, and nanoparticle coating. The effects of these changes were characterized through transmission electron microscopy (TEM), UV-Vis spectrometry (UV-Vis), Nuclear Magnetic Resonance spectroscopy (NMR) and Fourier Transform Infrared spectroscopy (FTIR). A unique aspect to this reaction is that usually silanes hydrolyze and cross-link in water; however, in this system the silane is water-soluble and stable. It is known that silicon and amino moieties can form complexes with metal salts. The silicon is known to extend its coordination sphere to form penta- or hexa-coordinated species. Furthermore, the silanol group can undergo hydrolysis to form a Si-O-Si silica network, thereby transforming the metal nanoparticles into a functionalized nanocomposites.

La reacción se controló por medio de espectrometría de UV-Vis como la formación de nanopartículas debe producir picos característicos para cada nanopartícula metálica individual. El análisis final de los materiales sintetizados se llevó a cabo a través de TEM y FTIR. Los espectros de FTIR se obtuvo a partir de polvo seco de muestras. El análisis del tamaño de partícula se puede lograr mediante la medición de diámetro de nanopartículas a partir de imágenes obtenidas a tr...

Watch this Scientific Journal Video about Generation of Zerovalent Metal Core Nanoparticles Using n-2-aminoethyl-3-aminosilanetriol at JoVE.com

Generation of Zerovalent Metal Core Nanoparticles Using n-2-aminoethyl-3-aminosilanetriol

A novel method for metal core nanoparticle synthesis using a water stable silanol is described.

Generación de valencia cero metal Core nanopartículas usando N- (2-aminoetil) -3-aminosilanetriol

In this work, a facile one-pot reaction for the formation of metal nanoparticles in a water solution through the use of ...

generation-zerovalent-metal-core-nanoparticles-using-n-2-aminoethyl-3

Research

JoVE Journal

Chemistry

Generation of Zerovalent Metal Core Nanoparticles Using n-(2-aminoethyl)-3-aminosilanetriol

7.6K vistas.  William Paterson University. A novel method for metal core nanoparticle synthesis using a water stable silanol is described.

Video: Generation of Zerovalent Metal Core Nanoparticles Using n-2-aminoethyl-3-aminosilanetriol

Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are encapsulated in polystyrene-block-poly(acrylic acid) (PSPAA) shells and then used as monomers for their self-assembly. Spherical PSPAA micelles upon acid treatment are known to assemble into cylindrical micelles. Exploiting this tendency, the core-shell nanoparticles are induced to aggregate, coalesce, and then transform into long chains. When more than one type of nanoparticles are used, random and block &#8220;copolymers&#8221; of nanoparticles can be obtained. Detailed procedures are reported for the PSPAA encapsulation of nanoparticles, homo- and co-polymerization of the core-shell nanoparticles, separation and purification of the resulting nanoparticle chains. Transformations of single-line chains into double- and triple-line chains are also presented. The synergy between the polymer shell and the embedded nanoparticles leads to an unusual chain-growth polymerization mode, giving long nanoparticle chains that are distinct from the products of the traditional step-growth aggregation process.

Using Polystyrene-block-polyacrylic acid-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We report protocols for &#8220;polymerizing&#8221; various types of polymer-encapsulated metal nanoparticles into long chains of &#8220;homo-&#8220; and &#8220;co-polymers&#8221;.

El uso de poliestireno<em&gt; Bloque</em&gt; Poli (ácido acrílico) presenta el revestimiento de metal nanopartículas como monómeros para su homo- y co-polimerización

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are ...

Investigación

Química

Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The silica-encapsulated metal oxide nanoparticles are then carburized in a methane/hydrogen atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal carbide nanoparticles. During the carburization process, the silica shells prevent the sintering of adjacent carbide nanoparticles while also preventing the deposition of excess surface carbon. Alternatively, the silica-encapsulated metal oxide nanoparticles can be nitridized in an ammonia atmosphere at temperatures over 800 &#176;C to form silica-encapsulated early transition metal nitride nanoparticles. By adjusting the reverse microemulsion parameters, the thickness of the silica shells, and the carburization/nitridation conditions, the transition metal carbide or nitride nanoparticles can be tuned to various sizes, compositions, and crystal phases. After carburization or nitridation, the silica shells are then removed using either a room-temperature aqueous ammonium bifluoride solution or a 0.1 to 0.5 M NaOH solution at 40-60 &#176;C. While the silica shells are dissolving, a high surface area support, such as carbon black, can be added to these solutions to obtain supported early transition metal carbide or nitride nanoparticles. If no high surface area support is added, then the nanoparticles can be stored as a nanodispersion or centrifuged to obtain a nanopowder.

A &#8220;removable ceramic coating method&#8221; is presented in visual format for the synthesis of non-sintered and metal-terminated monometallic and bimetallic early transition metal carbide and nitride nanoparticles with tunable sizes and crystal structures.

Síntesis microemulsión inversa mediada de monometálicos y bimetálico temprana de metal de transición de carburo y nitruro de nanopartículas

A reverse microemulsion is used to encapsulate monometallic or bimetallic early transition metal oxide nanoparticles in microporous silica shells. The ...

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

Síntesis, caracterización y funcionalización de híbridos Au / CdS y Au / ZnS Core / Shell nanopartículas

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

Síntesis y caracterización de supramoleculares Coloides

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

A Rapid Synthesis Method for Au, Pd, and Pt Aerogels Via Direct Solution-Based Reduction

Here, a method to synthesize gold, palladium, and platinum aerogels via a rapid, direct solution-based reduction is presented. The combination of various precursor noble metal ions with reducing agents in a 1:1 (v/v) ratio results in the formation of metal gels within seconds to minutes compared to much longer synthesis times for other techniques such as sol-gel. Conducting the reduction step in a microcentrifuge tube or small volume conical tube facilitates a proposed nucleation, growth, densification, fusion, equilibration model for gel formation, with final gel geometry smaller than the initial reaction volume. This method takes advantage of the vigorous hydrogen gas evolution as a by-product of the reduction step, and as a consequence of reagent concentrations. The solvent accessible specific surface area is determined with both electrochemical impedance spectroscopy and cyclic voltammetry. After rinsing and freeze drying, the resulting aerogel structure is examined with scanning electron microscopy, X-ray diffractometry, and nitrogen gas adsorption. The synthesis method and characterization techniques result in a close correspondence of aerogel ligament sizes. This synthesis method for noble metal aerogels demonstrates that high specific surface area monoliths may be achieved with a rapid and direct reduction approach.

A rapid, direct solution-based reduction synthesis method to obtain Au, Pd, and Pt aerogels is presented.

Un método de síntesis rápida de Au, Pd y Pt Aerogels vía reducción directa basada en la solución

Here, a method to synthesize gold, palladium, and platinum aerogels via a rapid, direct solution-based reduction is presented. The combination of various ...

Synthesis of Bimetallic Pt/Sn-based Nanoparticles in Ionic Liquids

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular physico-chemical properties of ionic liquids (ILs) are exploited to control both nucleation and growth processes. The nanoparticles form colloidal sols of very high colloidal stability in the IL, which is particularly interesting in view of their use as quasi-homogeneous catalysts. Procedures for both nanoparticle extraction in conventional solvents and for nanoparticle precipitation are presented. The size, structure and composition of the synthesized nanocrystals are confirmed using inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy (EDX). By this, we show that the nanocrystals are random-type alloy and of small (2-3 nm) size. The catalytic activity and selectivity in the hydrogenation of &#945;,&#946;-unsaturated aldehydes is tested in a semi-continuous batch-type reactor. In this context, the bimetallic Pt/Sn-based nanoparticles reveal a high selectivity towards the unsaturated alcohol.

A protocol for the synthesis of bimetallic nanoparticles in ionic liquids and the procedure of their catalytic testing in the selective hydrogenation of unsaturated aldehydes are described.

Síntesis de nanopartículas bimetálicas Pt/Sn-basados en líquidos iónicos

We demonstrate a method for the synthesis of bimetallic nanoparticles consisting of Pt and Sn. A synthesis strategy is used in which the particular ...

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared according to the methodology developed by surface organometallic chemistry (SOMC). In this framework, catalytic cycles can be determined by isolating crucial intermediates. All air-sensitive materials are handled under inert atmosphere (using gloveboxes or a Schlenk line) or high vacuum lines (HVLs, &#60;10-5 mbar). The preparation of SiO2-700 (silica dehydroxylated at 700 &#176;C) and subsequent applications (the grafting of complexes and catalytic runs) requires the use of HVLs and double-Schlenk techniques. Several well-known characterization methods are used, such as Fourier-transform infrared spectroscopy (FTIR), elemental microanalysis, solid-state nuclear magnetic resonance spectroscopy (SSNMR), and state-of-the-art dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP-SENS). FTIR and elemental microanalysis permit scientists to establish the grafting and its stoichiometry. 1H and 13C SSNMR allows the structural determination of the hydrocarbon ligands coordination sphere. DNP SENS is an emerging powerful technique in solid characterization for the detection of poorly sensitive nuclei (15N, in our case). SiO2-700 is treated with about one equivalent of the metal precursor compared to the amount of surface silanol (0.30 mmol&#183;g-1) in pentane at room temperature. Then, volatiles are removed, and the powder samples are dried under dynamic high vacuum to afford the desired materials [(&#8801;Si-O-)Hf(&#951;2&#960;-MeNCH2)(&#951;1-NMe2)(&#951;1-HNMe2)]. After a thermal treatment under high vacuum, the grafted complex is converted into metal imido silica complex [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)]. [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] effectively promotes the metathesis of imines, using the combination of two imine substrates, N-(4-phenylbenzylidene)benzylamine, or N-(4-fluorobenzylidene)-4-fluoroaniline, with N-benzylidenetert-butylamine as substrates. A significantly lower conversion is observed with the blank runs; thus, the presence of the imido group in [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is correlated to the catalytic performance.

A new group IV metal catalyst for imine metathesis is prepared by grafting amine metal complex onto dehydroxylated silica. Surface metal fragments are characterized using FT-IR, elemental microanalysis, and solid-state NMR spectroscopy. Further dynamic nuclear polarization surface enhanced NMR spectroscopy experiments complement the determination of the coordination sphere.

Imine Metathesis de Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared ...

Preparation of Silver-Palladium Alloyed Nanoparticles for Plasmonic Catalysis under Visible-Light Illumination

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles (NPs) can accelerate and control the selectivity of a variety of molecular transformations. This opens possibilities for the use of visible or near-IR light as a sustainable input to drive and control reactions when plasmonic nanoparticles supporting LSPR excitation in these ranges are employed as catalysts. Unfortunately, this is not the case for several catalytic metals such as palladium (Pd). One strategy to overcome this limitation is to employ bimetallic NPs containing plasmonic and catalytic metals. In this case, the LSPR excitation in the plasmonic metal can contribute to accelerate and control transformations driven by the catalytic component. The method reported herein focuses on the synthesis of bimetallic silver-palladium (Ag-Pd) NPs supported on ZrO2 (Ag-Pd/ZrO2) that acts as a plasmonic-catalytic system. The NPs were prepared by co-impregnation of corresponding metal precursors on the ZrO2 support followed by simultaneous reduction leading to the formation of bimetallic NPs directly on the ZrO2 support. The Ag-Pd/ZrO2 NPs were then used as plasmonic catalysts for the reduction of nitrobenzene under 425 nm illumination by LED lamps. Using gas chromatography (GC), the conversion and selectivity of the reduction reaction under the dark and light irradiation conditions can be monitored, demonstrating the enhanced catalytic performance and control over selectivity under LSPR excitation after alloying non-plasmonic Pd with plasmonic metal Ag. This technique can be adapted to a wide range of molecular transformations and NPs compositions, making it useful for the characterization of the plasmonic catalytic activity of different types of catalysis in terms of conversion and selectivity.

Presented here is a protocol for the synthesis of silver-palladium (Ag-Pd) alloy nanoparticles (NPs) supported on ZrO2 (Ag-Pd/ZrO2). This system allows for harvesting energy from visible light irradiation to accelerate and control molecular transformations. This is illustrated by nitrobenzene reduction under light irradiation catalyzed by Ag-Pd/ZrO2 NPs.

Preparación de nanopartículas de aleación silver-palladium para catálisis plásmiónica bajo iluminación de luz visible

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles (NPs) can accelerate and control the selectivity of a variety of molecular ...

Gold Nanoparticle Synthesis

Gold nanoparticles (Au nanoparticles) that are ~12 nm in diameter were synthesized by rapidly injecting a solution of 150 mg (0.15 mmol) of tetrachloroauric acid in 3.0 g (3.7 mmol, 3.6 mL) of oleylamine (technical grade) and 3.0 mL of toluene into a boiling solution of 5.1 g (6.4 mmol, 8.7 mL) of oleylamine in 147 mL of toluene. While boiling and mixing the reaction solution for 2 hours, the color of the reaction mixture changed from clear, to light yellow, to light pink, and then slowly to dark red. The heat was then turned off, and the solution was allowed to gradually cool down to room temperature for 1 hour. The gold nanoparticles were then collected and separated from the solution using a centrifuge and washed three times; by vortexing and dispersing the gold nanoparticles in 10 mL portions of toluene, and then precipitating the gold nanoparticles by adding 40 mL portions of methanol and spinning them in a centrifuge. The solution was then decanted to remove any remaining byproducts and unreacted starting materials. Drying the gold nanoparticles in a vacuum environment produced a solid black pellet; which could be stored for long periods of time (up to one year) for later use, and then redissolved in organic solvents such as toluene.

A protocol for synthesizing ~12 nm diameter gold nanoparticles (Au nanoparticles) in an organic solvent is presented. The gold nanoparticles are capped with oleylamine ligands to prevent agglomeration. The gold nanoparticles are soluble in organic solvents such as toluene.

Síntesis de nanopartículas de oro

Gold nanoparticles (Au nanoparticles) that are ~12 nm in diameter were synthesized by rapidly injecting a solution of 150 mg (0.15 mmol) of ...

Triplet Fusion Upconversion Nanocapsule Synthesis

Triplet fusion upconversion (UC) allows for the generation of one high energy photon from two low energy input photons. This well-studied process has significant implications for producing high energy light beyond a material's surface. However, the deployment of UC materials has been stymied due to poor material solubility, high concentration requirements, and oxygen sensitivity, ultimately resulting in reduced light output. Toward this end, nanoencapsulation has been a popular motif to circumvent these challenges, but durability has remained elusive in organic solvents. Recently, a nanoencapsulation technique was engineered to tackle each of these challenges, whereupon an oleic acid nanodroplet containing upconversion materials was encapsulated with a silica shell. Ultimately, these nanocapsules (NCs) were durable enough to enable triplet fusion upconversion-facilitated volumetric three-dimensional (3D) printing. By encapsulating upconversion materials with silica and dispersing them in a 3D printing resin, photopatterning beyond the surface of the printing vat was made possible. Here, video protocols for the synthesis of upconversion NCs are presented for both small-scale and large-scale batches. The outlined protocols serve as a starting point for adapting this encapsulation scheme to multiple upconversion schemes for use in volumetric 3D printing applications.

This protocol details the synthesis of upconversion nanocapsules for subsequent use in photopolymerizable resins for triplet fusion upconversion-facilitated volumetric 3D printing.

Síntesis de nanocápsulas de conversión ascendente de fusión triplete

Triplet fusion upconversion (UC) allows for the generation of one high energy photon from two low energy input photons. This well-studied process has ...