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>

<ol>
	<li>Corriu, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organosilicon+Chemistry+and+Nanoscience.">Organosilicon Chemistry and Nanoscience.</a> J Organomet Chem. 686, 32-41 (2003).</li><li>Chou, L. Y., Ming, K., Chan, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+for+the+intracellular+delivery+of+nanoparticles.">Strategies for the intracellular delivery of nanoparticles.</a> Chem. Soc. Rev. 40 (1), 233-245 (2011).</li><li>Richards, R., B&#246;nnemann, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthetic+Approaches+to+Metallic+Nanomaterials.">Synthetic Approaches to Metallic Nanomaterials.</a> Nanofabrication towards Biomedical Applications. , 4-9 (2005).</li><li>Bradley, J., Schmid, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+6,+Unit+6.2.2,+The+Chemistry+of+Transition+Metal+Colloids:+Synthetic+Methods+for+the+Preparation+of+Colloidal+Transition+Metals.">Chapter 6, Unit 6.2.2, The Chemistry of Transition Metal Colloids: Synthetic Methods for the Preparation of Colloidal Transition Metals.</a> Clusters and Colloids. , 469-473 (1994).</li><li>Paterer, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+on+the+formation+of+copper+zinc+tin+sulphide+nanoparticles+from+metal+salts+and+dodecanethiol.">Investigation on the formation of copper zinc tin sulphide nanoparticles from metal salts and dodecanethiol.</a> Mater. Chem. Phys. 149-150, 94-98 (2015).</li><li>Yi, D. K., Lee, S. S., Ying, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+Applications+of+Magnetic+Nanocomposite+Catalysts.">Synthesis and Applications of Magnetic Nanocomposite Catalysts.</a> Chem. Mater. 18, 2459-2461 (2006).</li><li>Piepenbrock, M. M., Lloyd, G. O., Clarke, N., Steed, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal-+and+Anion-Binding+Supramolecular+Gels.">Metal- and Anion-Binding Supramolecular Gels.</a> Chem. Rev. 110, 1960-2004 (2010).</li><li>Wu, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+Structural+Characterization+of+Novel+Nanohybrids+by+Cationic+3D+Silica+Nanoparticles+Sandwiched+between+2D+Anionic+Montmorillonite+Clay+through+Electrostatic+Attraction.">Preparation and Structural Characterization of Novel Nanohybrids by Cationic 3D Silica Nanoparticles Sandwiched between 2D Anionic Montmorillonite Clay through Electrostatic Attraction.</a> J. Phys. Chem. C. 113 (30), 13036-13044 (2009).</li><li>Spitalsky, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbon+nanotube-polymer+composites:+Chemistry,+Processing,+Mechanical+and+Electrical+Properties.">Carbon nanotube-polymer composites: Chemistry, Processing, Mechanical and Electrical Properties.</a> Prog. Polym. Sci. 35, 357-401 (2010).</li><li>Link, S., El-Sayed, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spectral+Properties+and+Relaxation+Dynamics+of+Surface+Plasmon+Electronic+Oscillations+in+Gold+and+Silver+Nanodots+and+Nanorods.">Spectral Properties and Relaxation Dynamics of Surface Plasmon Electronic Oscillations in Gold and Silver Nanodots and Nanorods.</a> J. Phys. Chem. B. 103 (40), 8410-8426 (1999).</li><li>Fau, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitoring+the+Coordination+of+Amine+Ligands+on+Silver+Nanoparticles+Using+NMR+and+SERS.">Monitoring the Coordination of Amine Ligands on Silver Nanoparticles Using NMR and SERS.</a> Langmuir. 31 (4), 1362-1367 (2015).</li><li>Patil, H. B., Borse, S. V., Patil, D. R., Patil, U. K., Patil, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+silver+nanoparticles+by+microbial+method+and+their+characterization.">Synthesis of silver nanoparticles by microbial method and their characterization.</a> Arch. Phys. Res. 2 (3), 153-158 (2011).</li><li>Ghosh, S., Sarma, N., Mandal, M., Kundu, S., Esumi, K., Pal, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolution+of+gold+nanoparticles+in+micelle+by+UV-irradiation:+A+conductometric+study.">Evolution of gold nanoparticles in micelle by UV-irradiation: A conductometric study.</a> Curr. Sci. 84 (6), 791-795 (2003).</li><li>Paul, B., Bhuyan, B., Purkayastha, D. D., Dey, M., Dhar, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Green+synthesis+of+gold+nanoparticles+using+Pogestemon+benghalensis+(B)+O.+Ktz+leaf+extract+and+studies+of+their+photocatalytic+activity+in+degradation+of+methylene.">Green synthesis of gold nanoparticles using Pogestemon benghalensis (B) O. Ktz leaf extract and studies of their photocatalytic activity in degradation of methylene.</a> Mater. Lett. 148, 37-40 (2015).</li><li>Chauhan, B. P. S., Rathore, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regioselective+Synthesis+of+Multifunctional+Hybrid+Polysiloxanes+Achieved+by+Pt-Nanocluster+Catalysis.">Regioselective Synthesis of Multifunctional Hybrid Polysiloxanes Achieved by Pt-Nanocluster Catalysis.</a> J. Am. Chem. Soc. 127, 5790-5791 (2005).</li><li>Chauhan, B. P. S., Rathore, S., Bandoo, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=&#34;Polysiloxane-Pd&#34;+Nanocomposites+as+Recyclable+Chemoselective+Hydrogenation+Catalysts.">&#34;Polysiloxane-Pd&#34; Nanocomposites as Recyclable Chemoselective Hydrogenation Catalysts.</a> J. Am. Chem. Soc. 126, 8493-8500 (2004).</li><li>Chauhan, B. P. S., Rathore, S., Chauhan, M., Krawicz, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+Polysiloxane+Stabilized+Palladium+Colloids+and+Evidence+of+Their+Participation+in+Silaesterification+Reactions.">Synthesis of Polysiloxane Stabilized Palladium Colloids and Evidence of Their Participation in Silaesterification Reactions.</a> J. Am. Chem. Soc. 125, 2876-2877 (2003).</li><li>Chauhan, B. P. S., Sardar, R., Tewari, P., Sharma, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> , 23-25 (2003).</li><li>Pouchert, C. J., Pouchert, C. .. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-Aromatic+Amines.">Non-Aromatic Amines.</a> The Aldrich Library of Infrared Spectra. , (1983).</li><li>Arkles, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Infrared+Analysis+of+Organosilicon+Compounds:+Spectra-Structure+Correlations.">Infrared Analysis of Organosilicon Compounds: Spectra-Structure Correlations.</a> Silicon Compounds Register and Review. , (1987).</li><li>Corriu, R. J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypervalent+Species+of+Silicon-structure+and+Reactivity.">Hypervalent Species of Silicon-structure and Reactivity.</a> J. Organomet. Chem. 400, 81-106 (1990).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Basic Instruction Manual: Hitachi HT7700 TEM. , 1-28 (2014).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> OMNIC User's Guide Version 7.3: Thermo Electron Corporation. , 151-216 (2006).</li></ol>

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 border="0" cellpadding="0" cellspacing="0" width="644">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:287px;">n-(2-aminoethyl)-3-aminosilanetriol (2-AST)</td>
			<td style="width:209px;">Gelest</td>
			<td style="width:72px;">SIA0590.0</td>
			<td style="width:76px;">25% in H2O</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Silver nitrate</td>
			<td>Sigma Aldrich</td>
			<td>S6506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Gold(III) chloride trihydrate</td>
			<td>Sigma Aldrich</td>
			<td align="right">520918</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Palladium(II) Nitrate</td>
			<td>Alfa Aesar</td>
			<td align="right">11035</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">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 ...

Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod

Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, this resolution provides records at the annual to decadal scale, at best. An extrusion method, using a calibrated, threaded-rod is presented here, which allows for millimeter-scale subsampling of aquatic sediment cores of varying diameters. Millimeter scale subsampling allows for sub-annual to monthly analysis of the sedimentary record, an order of magnitude higher than typical sampling schemes. The extruder consists of a 2 m aluminum frame and base, two core tube clamps, a threaded-rod, and a 1 m piston. The sediment core is placed above the piston and clamped to the frame. An acrylic sampling collar is affixed to the upper 5 cm of the core tube and provides a platform from which to extract sub-samples. The piston is rotated around the threaded-rod at calibrated intervals and gently pushes the sediment out the top of the core tube. The sediment is then isolated into the sampling collar and placed into an appropriate sampling vessel (e.g., jar or bag). This method also preserves the unconsolidated samples (i.e., high pore water content) at the surface, providing a consistent sampling volume. This mm scale extrusion method was applied to cores collected in the northern Gulf of Mexico following the Deepwater Horizon submarine oil release. Evidence suggests that it is necessary to sample at the mm scale to fully characterize events that occur on the monthly time-scale for continental slope sediments.

An extrusion method using a calibrated threaded-rod is presented, which allows for mm scale subsampling of aquatic sediment cores. Millimeter-scale sampling is necessary to fully characterize recent event stratigraphy in sediment records.

Método de extrusión de sedimentos Core con una resolución milimétrica Utilizando una varilla roscada-calibrado

Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, ...

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. They offer new possibilities for the characterization of living systems and are particularly appropriate for detecting, localizing and quantifying the presence of metal oxide nanoparticles both in biological specimens and the environment. Indeed, these techniques all meet relevant requirements in terms of (i) sensitivity (from 1 up to 10 &#181;g.g-1 of dry mass), (ii) micrometer range spatial resolution, and (iii) multi-element detection. Given these characteristics, microbeam chemical element imaging can powerfully complement routine imaging techniques such as optical and fluorescence microscopy. This protocol describes how to perform a nuclear microprobe analysis on cultured cells (U2OS) exposed to titanium dioxide nanoparticles. Cells must grow on and be exposed directly in a specially designed sample holder used on the optical microscope and in the nuclear microprobe analysis stages. Plunge-freeze cryogenic fixation of the samples preserves both the cellular organization and the chemical element distribution. Simultaneous nuclear microprobe analysis (scanning transmission ion microscopy, Rutherford backscattering spectrometry and particle induced X-ray emission) performed on the sample provides information about the cellular density, the local distribution of the chemical elements, as well as the cellular content of nanoparticles. There is a growing need for such analytical tools within biology, especially in the emerging context of Nanotoxicology and Nanomedicine for which our comprehension of the interactions between nanoparticles and biological samples must be deepened. In particular, as nuclear microprobe analysis does not require nanoparticles to be labelled, nanoparticle abundances are quantifiable down to the individual cell level in a cell population, independently of their surface state.

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

We describe a procedure for the detection of chemical elements present in situ in human cells as well as their in vitro quantification. The method is well-suited to any cell type and is particularly useful for quantitative chemical analyses in single cells following in vitro metal oxide nanoparticles exposure.

In Situ Detección y cuantificación de la célula de las nanopartículas de óxido de Metal usando análisis de microsonda Nuclear

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. ...

Determination of Thermodynamic Properties of Alkaline Earth-liquid Metal Alloys Using the Electromotive Force Technique

A novel electrochemical cell based on a CaF2 solid-state electrolyte has been developed to measure the electromotive force (emf) of binary alkaline earth-liquid metal alloys as functions of both composition and temperature in order to acquire thermodynamic data. The cell consists of a chemically stable solid-state CaF2-AF2 electrolyte (where A is the alkaline-earth element such as Ca, Sr, or Ba), with binary A-B alloy (where B is the liquid metal such as Bi or Sb) working electrodes, and a pure A metal reference electrode. Emf data are collected over a temperature range of 723 K to 1,123 K in 25 K increments for multiple alloy compositions per experiment and the results are analyzed to yield activity values, phase transition temperatures, and partial molar entropies/enthalpies for each composition.

This protocol describes the measurement of the electromotive force of alkaline-earth elements in liquid metal alloys at high temperatures (723-1,123 K) to determine their thermodynamic properties, including activity, partial molar entropy, partial molar enthalpy, and phase transition temperatures, over a wide composition range.

Determinación de propiedades termodinámicas de aleaciones de metales alcalinotérreos-líquido utilizando la técnica de la fuerza electromotriz

A novel electrochemical cell based on a CaF2 solid-state electrolyte has been developed to measure the electromotive force (emf) of binary alkaline ...

Ligand-Mediated Nucleation and Growth of Palladium Metal Nanoparticles

The size, size distribution and stability of colloidal nanoparticles are greatly affected by the presence of capping ligands. Despite the key contribution of capping ligands during the synthesis reaction, their role in regulating the nucleation and growth rates of colloidal nanoparticles is not well understood. In this work, we demonstrate a mechanistic investigation of the role of trioctylphosphine (TOP) in Pd nanoparticles in different solvents (toluene and pyridine) using in situ SAXS and ligand-based kinetic modeling. Our results under different synthetic conditions reveal the overlap of nucleation and growth of Pd nanoparticles during the reaction, which contradicts the LaMer-type nucleation and growth model. The model accounts for the kinetics of Pd-TOP binding for both, the precursor and the particle surface, which is essential to capture the size evolution as well as the concentration of particles in situ. In addition, we illustrate the predictive power of our ligand-based model through designing the synthetic conditions to obtain nanoparticles with desired sizes. The proposed methodology can be applied to other synthesis systems and therefore serves as an effective strategy for predictive synthesis of colloidal nanoparticles.

The main goal of this work is to elucidate the role of capping agents in regulating the size of palladium nanoparticles by combining in situ small angle x-ray scattering (SAXS) and ligand-based kinetic modeling.

Mediada por el ligando de la nucleación y crecimiento de nanopartículas de Metal de paladio

The size, size distribution and stability of colloidal nanoparticles are greatly affected by the presence of capping ligands. Despite the key contribution ...

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. Here, we introduce the molten-salt synthesis (MSS) method for making metal oxide nanomaterials. Advantages over other methods include its simplicity, greenness, reliability, scalability, and generalizability. Using pyrochlore lanthanum hafnium oxide (La2Hf2O7) as a representative, we describe the MSS protocol for the successful synthesis of complex metal oxide nanoparticles (NPs). Furthermore, this method has the unique ability to produce NPs with different material features by changing various synthesis parameters such as pH, temperature, duration, and post-annealing. By fine-tuning these parameters, we are able to synthesize highly uniform, non-agglomerated, and highly crystalline NPs. As a specific example, we vary the particle size of the La2Hf2O7&#160;NPs by changing the concentration of the ammonium hydroxide solution used in the MSS process, which allows us to further explore the effect of particle size on various properties. It is expected that the MSS method will become a more popular synthesis method for nanomaterials and more widely employed in the nanoscience and nanotechnology community in the upcoming years.

Here, we demonstrate a unique, relatively low-temperature, molten-salt synthesis method for preparing uniform complex metal oxide lanthanum hafnate nanoparticles.

Sales fundidas síntesis de nanopartículas de óxidos metálicos complejos

The development of feasible synthesis methods is critical for the successful exploration of novel properties and potential applications of nanomaterials. ...

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis

Heteroarylation introduces heteroaryl fragments to organic molecules. Despite the numerous available reactions reported for arylation via transition metal catalysis, the literature on direct heteroarylation is scarce. The presence of heteroatoms such as nitrogen, sulfur and oxygen often make heteroarylation a challenging research field due to catalyst poisoning, product decomposition and the rest. This protocol details a highly efficient direct &#945;-C(sp3) heteroarylation of ketones under microwave irradiation. Key factors for successful heteroarylation include the use of XPhos Palladacycle Gen. 4 Catalyst, excess base to suppress side reactions and the high temperature and pressure achieved in a sealed reaction vial under microwave irradiation. The heteroarylation compounds prepared by this method were fully characterized by proton nuclear magnetic resonance spectroscopy (1H NMR), carbon nuclear magnetic resonance spectroscopy (13C NMR) and high-resolution mass spectrometry (HRMS). This methodology has several advantages over literature precedents including broad substrate scope, rapid reaction time, greener procedure and operational simplicity by eliminating the preparation of intermediates such as silyl enol ether. Possible applications for this protocol include, but are not limited to, diversity-oriented synthesis for the discovery of biologically active small molecules, domino synthesis for the preparation of natural products and ligand development for new transition metal catalytic systems.

Heteroaryl compounds are important molecules utilized in organic synthesis, medicinal and biological chemistry. A microwave-assisted heteroarylation using palladium catalysis provides a rapid and efficient method to attach heteroaryl moieties directly to ketone substrates.

Una heterolación directa asistida por microondas de cetonas mediante la catálisis de metal de transición

Heteroarylation introduces heteroaryl fragments to organic molecules. Despite the numerous available reactions reported for arylation via transition metal ...

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks (MOFs)

Substrate size discrimination by the pore size and homogeneity of the chiral environment at the reaction sites are important issues in the validation of the reaction site in metal-organic framework (MOF)&#8211;based catalysts in an enantioselective catalytic reaction system. Therefore, a method of validating the reaction site of MOF-based catalysts is necessary to investigate this issue. Substrate size discrimination by pore size was accomplished by comparing the substrate size versus the reaction rate in two different types of carbonyl-ene reactions with two kinds of MOFs. The MOF catalysts were used to compare the performance of the two reaction types (Zn-mediated stoichiometric and Ti-catalyzed carbonyl-ene reactions) in two different media. Using the proposed method, it was observed that the entire MOF crystal participated in the reaction, and the interior of the crystal pore played an important role in exerting chiral control when the reaction was stoichiometric. Homogeneity of the chiral environment of MOF catalysts was established by the size control method for a particle used in the Zn-mediated stoichiometric reaction system. The protocol proposed for the catalytic reaction revealed that the reaction mainly occurred on the catalyst surface regardless of the substrate size, which reveals the actual reaction sites in MOF-based heterogeneous catalysts. This method for reaction site validation of MOF catalysts suggests various considerations for developing heterogeneous enantioselective MOF catalysts.

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs

Here, we present a protocol for active site validation of metal-organic framework catalysts by comparing stoichiometric and catalytic carbonyl-ene reactions to find out whether a reaction takes place on the inner or outer surface of metal-organic frameworks.

Desarrollo de catalizadores enantioselectivos heterogéneos utilizando marcos metálicos-orgánicos quirales (MOF)

Substrate size discrimination by the pore size and homogeneity of the chiral environment at the reaction sites are important issues in the validation of ...