Os autores estendem sua apreciação ao Dr. Thomas J. Emge e ao Wei Liu da universidade de Rutgers para sua análise e perícia na difração do raio X do ângulo pequeno e na difração de raio X do pó. Além disso, os autores reconhecem Hao Wang por seu apoio com as experiências de adsorção de N2.

1. Síntese de nanopartículas de Al (OH) 3 <ol><li> Dissolver 1,40 g de hexahidrato de cloreto de alumínio em 5,822 g de água desionizada. </li><li> Adicionar 2,778 g de L-arginina à solução aquosa de cloreto de alumínio sob agitação magnética. Adicione a L-arginina lentamente, de modo que a arginina adicionada se dissolva e não forme grandes aglomerados ou pedaços; Além disso, uma adição lenta reduz as concentrações locais de alcalinidade e proporciona condições para uma hidrólise mais controlável. </li><li> Uma vez que toda a arginina se dissolve na solução, aquecer a solução durante 72 h a 50 ° C; Neste momento, a solução pode aparecer como uma suspensão turva. </li></ol> 2. Precipitação de Al (OH) 3 com NaCl <ol><li> Preparar uma coluna de GPC que é de 49 polegadas de comprimento e 1,125 de diâmetro. Embalar o gel em etapas sucessivas de adicionar o gel e de permitir que a água flua através da coluna para assegurar a embalagem apropriada, com espaço mínimo entre os grânulos do gel. Empacota oGel a cerca de 80% da coluna; A quantidade de gel embalado varia de cada vez e afecta apenas o tempo de retenção das espécies separadas. </li><li> Introduzir 10 mL de suspensão de nanopartículas de Al (OH) 3 sintetizada (preparada no passo 1.3) na coluna utilizando uma bomba de HPLC com um ciclo injector de 10 mL. Custom-fazer o loop injetor usando tubulação com um diâmetro externo de aproximadamente 0,125 polegadas e um comprimento que é calibrado para entregar 10 mL de amostra injetada. </li><li> Recolher a coluna de eluição em intervalos de correlação com a localização dRI pico. Conecte a saída GPC à entrada de um detector de índice de refração diferencial (dRI). NOTA: À medida que as espécies separadas saem do GPC, elas aparecem no detector de dRI como um pico e são então coletadas em frascos de 125 mL. A coluna GPC produz dois picos bem resolvidos, que são ambos recolhidos e analisados ​​com cromatografia de exclusão de tamanho (SEC) e análise elementar (EA) para discernir arginina a partir de alumínio speCias. O volume total recolhido dependerá do tamanho da coluna de GPC, da quantidade total de material de empacotamento utilizado e do caudal da água desionizada utilizada para eluir a coluna. <ol><li> Recolher a maioria da fracção do pico 1 ao longo de 100 min a uma taxa de fluxo de 0,2 mL / min. </li><li> Recolher o eluente em intervalos de 30 minutos uma vez que um pico emerge no detector RI da coluna GPC. NOTA: A alteração do intervalo de intervalos irá alterar a concentração ea pureza do material de pico 1 purificado resultante. É melhor recolher pequenos intervalos do pico no início para determinar qual parte contém a maior concentração e pureza de pico 1 espécie para uma coluna específica. </li></ol></li><li> Preparar 1% em peso de NaCl. </li><li> Adicionar a solução preparada de NaCl gota a gota a 10 mL de nanopartículas de Al (OH) 3 purificadas; O material preparado usando precipitação de NaCl não é usado para experiências adicionais. </li></ol> 3. Preparação de Al-MCM-41 <ol><li> AcSe aproximadamente 1,0 g de MCM-41 a 120 ° C sob vácuo durante 3 h num forno de vácuo. </li><li> Preparar 50,0 g de solução de cloreto de alumínio combinando 9,6926 g de AlCl3.6H2O com 40.3074 g de água desionizada. </li><li> Adicionar 0,7 g de MCM-41 activado a 50,0 g de uma solução de cloreto de alumínio (preparada no passo 3.2). </li><li> Deixar um tempo de mistura adequado (1 h) para assegurar a homogeneidade do AlCl 3 difundido através dos canais MCM-41. </li><li> Adicionar L-arginina à mistura heterogénea até uma razão molar Arg / Al de 2,75 sob agitação magnética. De forma semelhante ao passo 1.2, adicionar a arginina devagar o suficiente de modo a permitir que os floculados formados instantaneamente redissolvam e reduzam o agrupamento da arginina antes de continuar a adição. </li><li> Uma vez homogéneo, aquecer a mistura a 50 ° C durante 72 h. </li><li> Filtrar a solução heterogénea obtida utilizando um funil de Buchner, sob vácuo e equipado com círculos de papel de filtro qualitativo de 90 mm(Ou quaisquer outros papéis de filtro apropriados). </li><li> Lavar o pó branco filtrado com água desionizada em excesso para assegurar a remoção de cloreto de alumínio, arginina ou subprodutos solúveis em água não reagidos do material produzido Al-MCM-41. </li></ol>

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P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proton+Environments+in+Hydrous+Aluminosilicate+Glasses:+A+1H+MAS,+1H/27Al,+and+1H/23Na+TRAPDOR+NMR+Study.">Proton Environments in Hydrous Aluminosilicate Glasses: A 1H MAS, 1H/27Al, and 1H/23Na TRAPDOR NMR Study.</a> J. Phys. Chem. B. 103 (35), 7406-7415 (1999).</li><li>Kao, H. M., Grey, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Probing+the+Bronsted+and+Lewis+acidity+of+zeolite+HY:+A+1H/27Al+and+15N/27Al+TRAPDOOR+NMR+study+of+mono-methylamine+adsorbed+on+HY.">Probing the Bronsted and Lewis acidity of zeolite HY: A 1H/27Al and 15N/27Al TRAPDOOR NMR study of mono-methylamine adsorbed on HY.</a> J. Phys. Chem. 100 (12), 5105-5117 (1996).</li><li>DeCanio, E. C., Edwards, J. C., Bruno, J. 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Os autores não têm nada a revelar.

A preparação de uma solução aquosa de cloreto de alumínio implicou a utilização de um sal de hexahidrato cristalino de cloreto de alumínio. Embora a forma anidra possa também ser utilizada, não é preferida devido às suas propriedades higroscópicas significativas, o que torna difícil trabalhar com e controlar a concentração de alumínio. É de notar que a solução de cloreto de alumínio deve ser utilizada dentro de vários dias de preparação, porque ao longo do tempo, o hidrato de ácido [Al (H 2...

Materiais feitos de hidróxido de alumínio são candidatos promissores para uma variedade de aplicações industriais, incluindo catálise, produtos farmacêuticos, tratamento de água e cosméticos. 1 , 2 , 3 , 4 A temperaturas elevadas, o hidróxido de alumínio absorve uma quantidade substancial de calor durante a decomposição para produzir alumina (Al2O3), tornando-o um agente retardador de chama útil. 5 Os quatro polimorfos conhecidos de hidróxido de alumínio ( isto é , gibbsite, bayerita, nordstrandita e doyleite) foram investigados usando técnicas computacionais e experimentais para melhorar nossa compreensão da formação e suas estruturas 6 . A preparação de partículas em nanoescala é de particular interesse devido ao seu potencial para exibir efeitos quânticos e propriedades diferentes das doR em massa. As partículas de nanogibbsite com dimensões da ordem de 100 nm são facilmente preparadas sob várias condições 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 . Superar os desafios inerentes associados com a redução dos tamanhos de partículas é ainda mais difícil; Portanto, existem apenas alguns casos em que as partículas de nanogibbsite têm dimensões da ordem de 50 nm. 14 , 15 , 16 , 17 Até onde sabemos, não houve relatos de nanogibbsite partículas menores do que 50 nm. Em parte, isso é atribuído ao fato de que as nanopartículas tendem a se aglomerar devido à instabilidade eletrostáticaE a elevada probabilidade de formação de ligações de hidrogénio entre as partículas coloidais, especialmente em solventes próticos polares. Nosso objetivo foi sintetizar pequenas nanopartículas de Al (OH) 3 usando ingredientes e precursores exclusivamente seguros. No presente trabalho, a agregação de partículas aquosas foi inibida pela incorporação de um aminoácido ( isto é , L-arginina) como um tampão e estabilizador. Além disso, é relatado que a arginina contendo guanidínio impediu o crescimento e a agregação de partículas de hidróxido de alumínio para produzir uma suspensão coloidal aquosa com tamanhos de partícula médio de 10-30 nm. Propõe-se aqui que as propriedades anfotéricas e zwitteriónicas da arginina atenuaram a carga superficial de nanopartículas de hidróxido de alumínio durante a hidrólise suave para desfavorecer o crescimento de partículas para além de 30 nm. Embora a arginina não fosse capaz de reduzir o tamanho de partícula abaixo de 10 nm, tais partículas foram conseguidas tirando partido do efeito de confinamento de &quot;gaiola&quot;Hin os mesopores de MCM-41. A caracterização do material compósito Al-MCM-41 revelou nanopartículas de hidróxido de alumínio ultrafinas dentro da sílica mesoporosa, que tem um tamanho médio de poro de 2,7 nm.

<table border="0" cellpadding="0" cellspacing="0" width="650">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">aluminum chloride hexahydrate</td>
			<td style="width:103px;">Alfa Aesar</td>
			<td align="right" style="width:119px;">12297</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">L-arginine</td>
			<td style="width:103px;">BioKyowa</td>
			<td style="width:119px;">N/A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">aluminum hydroxide</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td align="right" style="width:119px;">239186</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">Bio-Gel P-4 Gel</td>
			<td style="width:103px;">Bio-Rad</td>
			<td style="width:119px;">150-4128</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:261px;">Mesoporous siica (MCM-41 type)</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td align="right" style="width:119px;">643645</td>
			<td></td>
		</tr>
	</tbody>
</table>

facile preparation of ultrafine aluminum hydroxide particles with or without mesoporous mcm-41 in ambient environments

Uma suspensão aquosa de nanogibbsite foi sintetizada através da titulação de ácido-alumínio [Al (H 2 O) 6 ] 3+ com L-arginina a pH 4,6. Uma vez que a hidrólise de sais de alumínio aquosos é conhecida por produzir uma vasta gama de produtos com uma vasta gama de distribuições de tamanhos, uma variedade de instrumentos de última geração ( isto é, 27 Al / 1H NMR, FTIR, ICP-OES , TEM-EDX, XPS, XRD e BET) para caracterizar os produtos de síntese e identificação de subprodutos. O produto, que era constituído por nanopartículas (10-30 nm), foi isolado utilizando a técnica de coluna de cromatografia de permeação em gel (GPC). A espectroscopia de infravermelho de transformada de Fourier (FTIR) e a difração de raios X em pó (PXRD) identificaram o material purificado como polimorfo de gibbsite de hidróxido de alumínio. A adição de sais inorgânicos ( eg , NaCl) induziu a desestabilização electrostática da suspensão, aglomerando assim as nanopartículas a yieLd Al (OH) 3 precipitado com grandes tamanhos de partícula. Utilizando o novo método sintético aqui descrito, Al (OH) 3 foi parcialmente carregado dentro da estrutura mesoporosa altamente ordenada de MCM-41, com dimensões médias dos poros de 2,7 nm, produzindo um material de aluminosilicato com Al (O h / Td = 1,4). O teor total de Al, medido utilizando espectrometria de raios X de dispersão de energia (EDX), foi 11% p / p com uma razão molar Si / Al de 2,9. Uma comparação de EDX em massa com a análise elementar de espectroscopia de fotoelétrons de raios-X de superfície (XPS) forneceu uma visão sobre a distribuição de Al dentro do material de aluminosilicato. Além disso, foi observada uma proporção mais elevada de Si / Al na superfície externa (3.6) em comparação com a massa (2.9). As aproximações das relações O / Al sugerem uma concentração mais alta de grupos Al (O) 3 e Al (O) 4 próximos ao núcleo e à superfície externa, respectivamente. A síntese recentemente desenvolvida de Al-MCM-41 produz umMantendo a integridade da estrutura de sílica ordenada e pode ser utilizado para aplicações em que as nanopartículas de Al2O3 hidratadas ou anidras são vantajosas.

Síntese de Nanogibbsite O Nanogibbsite foi preparado por titulação de AlCl3.6H2O (14% em peso) com L-arginina até uma razão molar Arg / Al final de 2,75. A síntese de partículas de nanogibbsite foi monitorizada através de SEC, que é uma técnica de análise amplamente utilizada para soluções de cloreto de alumínio parcialmente hidrolisadas, capaz de discernir cinco domínios arbitrariamente designados como pi...

Watch this Scientific Journal Video about Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments at JoVE.com

Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

Uma suspensão de nanopartículas de hidróxido de alumínio ultrafino foi preparada através da titulação controlada de [Al (H2O)] 3+ com L-arginina até pH 4.6 com e sem confinamento de efeito de gaiola dentro de canais mesoporosos de MCM-41.

Facile Preparação de Partículas de Hidróxido de Alumínio Ultrafino com ou sem Mesoporous MCM-41 em Ambientes Ambientais

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis ...

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10.8K visualizações.  Colgate-Palmolive Company.  Uma suspensão de nanopartículas de hidróxido de alumínio ultrafino foi preparada através da titulação controlada de [Al (H2O)] 3+ com L-arginina até pH 4.6 com e sem confinamento de efeito de gaiola dentro de canais mesoporosos de MCM-41. 

Vídeo: Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

Particles without a Box: Brush-first Synthesis of Photodegradable PEG Star Polymers under Ambient Conditions

Convenient methods for the rapid, parallel synthesis of diversely functionalized nanoparticles will enable discovery of novel formulations for drug delivery, biological imaging, and supported catalysis. In this report, we demonstrate parallel synthesis of brush-arm star polymer (BASP) nanoparticles by the &#34;brush-first&#34; method. In this method, a norbornene-terminated poly(ethylene glycol) (PEG) macromonomer (PEG-MM) is first polymerized via ring-opening metathesis polymerization (ROMP) to generate a living brush macroinitiator. Aliquots of this initiator stock solution are added to vials that contain varied amounts of a photodegradable bis-norbornene crosslinker. Exposure to crosslinker initiates a series of kinetically-controlled brush+brush and star+star coupling reactions that ultimately yields BASPs with cores comprised of the crosslinker and coronas comprised of PEG. The final BASP size depends on the amount of crosslinker added. We carry out the synthesis of three BASPs on the benchtop with no special precautions to remove air and moisture. The samples are characterized by gel permeation chromatography (GPC); results agreed closely with our previous report that utilized inert (glovebox) conditions. Key practical features, advantages, and potential disadvantages of the brush-first method are discussed.

Poly(ethylene glycol) (PEG) brush-arm star polymers (BASPs) with narrow mass distributions and tunable nanoscopic sizes are synthesized in via ring opening metathesis polymerization (ROMP) of a PEG-norbornene macromonomer followed by transfer of portions of the resulting living brush initiator to vials containing varied amounts of a rigid, photo-cleavable bis-norbornene crosslinker.

Partículas sem Box: Brush-primeiro Síntese de fotodegradáveis ​​PEG Estrelas Polímeros em condições ambientais

Convenient methods for the rapid, parallel synthesis of diversely functionalized nanoparticles will enable discovery of novel formulations for drug ...

Química

Activating Molecules, Ions, and Solid Particles with Acoustic Cavitation

The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic cavitation: the nucleation, growth, and implosive collapse of microbubbles in liquids submitted to power ultrasound. The violent implosion of bubbles leads to the formation of chemically reactive species and to the emission of light, named sonoluminescence. In this manuscript, we describe the techniques allowing study of extreme intrabubble conditions and chemical reactivity of acoustic cavitation in solutions. The analysis of sonoluminescence spectra of water sparged with noble gases provides evidence for nonequilibrium plasma formation. The photons and the "hot" particles generated by cavitation bubbles enable to excite the non-volatile species in solutions increasing their chemical reactivity. For example the mechanism of ultrabright sonoluminescence of uranyl ions in acidic solutions varies with uranium concentration: sonophotoluminescence dominates in diluted solutions, and collisional excitation contributes at higher uranium concentration. Secondary sonochemical products may arise from chemically active species that are formed inside the bubble, but then diffuse into the liquid phase and react with solution precursors to form a variety of products. For instance, the sonochemical reduction of Pt(IV) in pure water provides an innovative synthetic route for monodispersed nanoparticles of metallic platinum without any templates or capping agents. Many studies reveal the advantages of ultrasound to activate the divided solids. In general, the mechanical effects of ultrasound strongly contribute in heterogeneous systems in addition to chemical effects. In particular, the sonolysis of PuO2 powder in pure water yields stable colloids of plutonium due to both effects.

Acoustic cavitation in liquids submitted to power ultrasound creates transient extreme conditions inside the collapsing bubbles, which are the origin of unusual chemical reactivity and light emission, known as sonoluminescence. In the presence of noble gases, nonequilibrium plasma is formed. The "hot" particles and the photons generated by collapsing bubbles are able to excite species in solution.

Ativando moléculas, íons e partículas sólidas com Acústico cavitação

The chemical and physical effects of ultrasound arise not from a direct interaction of molecules with sound waves, but rather from the acoustic ...

Synthesis and Catalytic Performance of Gold Intercalated in the Walls of Mesoporous Silica

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties of the materials were investigated. We used a one pot sol-gel approach to intercalate gold nano particles in the walls of mesoporous silica. To start with the synthesis, P123 was used as template to form micelles. Then TESPTS was used as a surface modification agent to intercalate gold nano particles. Following this process, TEOS was added in as a silica source which underwent a polymerization process in acid environment. After hydrothermal processing and calcination, the final product was acquired. Several techniques were utilized to characterize the porosity, morphology and structure of the gold intercalated mesoporous silica. The results showed a stable structure of mesoporous silica after gold intercalation. Through the oxidation of benzyl alcohol as a benchmark reaction, the GMS materials showed high selectivity and recyclability.

Here, we present a protocol with a sol-gel process to synthesize gold intercalated in the walls of mesoporous materials (GMS), which is confirmed to possess a mesoporous matrix with gold intercalated in the walls imparting great stability and recyclability.

Síntese e desempenho catalítico de ouro intercalados nas paredes de mesoporosos Silica

As a promising catalytically active nano reactor, gold nanoparticles intercalated in mesoporous silica (GMS) were successfully synthesized and properties ...

Facile and Efficient Preparation of Tri-component Fluorescent Glycopolymers via RAFT-controlled Polymerization

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and efficient synthesis of well-controlled fluorescent statistical glycopolymers using reversible addition-fragmentation chain-transfer (RAFT)-based polymerization is demonstrated. The synthesis starts with the preparation of &#946;-galactose-containing glycomonomer 2-lactobionamidoethyl methacrylamide obtained by reaction of lactobionolactone and N-(2-aminoethyl) methacrylamide (AEMA). 2-Gluconamidoethyl methacrylamide (GAEMA) is used as a structural analog lacking a terminal &#946;-galactoside. The following RAFT-mediated copolymerization reaction involves three different monomers: N-(2-hydroxyethyl) acrylamide as spacer, AEMA as target for further fluorescence labeling, and the glycomonomers. Tolerant of aqueous systems, the RAFT agent used in the reaction is (4-cyanopentanoic acid)-4-dithiobenzoate. Low dispersities (&#8804;1.32), predictable copolymer compositions, and high reproducibility of the polymerizations were observed among the products. Fluorescent polymers are obtained by modifying the glycopolymers with carboxyfluorescein succinimidyl ester targeting the primary amine functional groups on AEMA. Lectin-binding specificities of the resulting glycopolymers are verified by testing with corresponding agarose beads coated with specific glycoepitope recognizing lectins. Because of the ease of the synthesis, the tight control of the product compositions and the good reproducibility of the reaction, this protocol can be translated towards preparation of other RAFT-based glycopolymers with specific structures and compositions, as desired.

An efficient, three-step synthesis of RAFT-based fluorescent glycopolymers, consisting of glycomonomer preparation, copolymerization, and post-modification, is demonstrated. This protocol can be used to prepare RAFT-based statistical glycopolymers with desired structures.

Preparação fácil e eficiente de glicopolímeros fluorescentes Tri-componente via polimerização controlada pelo JANGADA

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and ...

Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates

Functions of clusters in nano or sub-nano scale significantly depend on not only kinds of their components but also arrangements, or symmetry, of their components. Therefore, the arrangements in the clusters have been precisely characterized, especially for metal complexes. Contrary to this, characterizations of molecular arrangements in supramolecular clusters composed of organic molecules are limited to a few cases. This is because construction of the supramolecular clusters, especially obtaining a series of the supramolecular clusters, is difficult due to low stability of non-covalent bonds compare to covalent bonds. From this viewpoint, utilization of organic salts is one of the most useful strategies. A series of the supramolecules could be constructed by combinations of a specific organic molecule with various counter ions. Especially, primary ammonium carboxylates are suitable as typical examples of supramolecules because various kinds of carboxylic acids and primary amines are commercially available, and it is easy to change their combinations. Previously, it was demonstrated that primary ammonium triphenylacetates using various kinds of primary amines specifically construct supramolecular clusters, which are composed of four ammoniums and four triphenylacetates assembled by charge-assisted hydrogen bonds, in crystals obtained from non-polar solvents. This study demonstrates an application of the specific construction of the supramolecular clusters as a strategy to conduct systematical symmetric study for clarification of correlations between molecular arrangements in supramolecules and kinds and numbers of their components. In the same way with binary salts composed of triphenylacetates and one kind of primary ammoniums, ternary organic salts composed of triphenylacetates and two kinds of ammoniums construct the supramolecular clusters, affording a series of the supramolecular clusters with various kinds and numbers of the components.

This article describes construction of a series of hydrogen-bonding supramolecular clusters in crystals using primary ammonium triphenylacetates, which are recrystallized from non-polar solvents. This selective construction of the supramolecular clusters leads to effective systematical symmetric studies about a correlation between the supramolecular clusters and their components.

Construção e sistemática simétricas Estudos de uma série de Supramoleculares Clusters com binários ou ternários Triphenylacetates Amônio

Functions of clusters in nano or sub-nano scale significantly depend on not only kinds of their components but also arrangements, or symmetry, of their ...

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G&#39; bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy.

We report on a smart application of carbon nanotubes for kinetic stabilization of lipid particles that contain self-assembled nanostructures in their cores. The preparation of lipid particles requires rather low concentrations of carbon nanotubes permitting their use in biomedical applications such as drug delivery.

Preparação Facile da Internamente auto-montados Lipid partículas estabilizada por nanotubos de carbono

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled ...

Facile Preparation of 4-Substituted Quinazoline Derivatives

Reported in this paper is a very simple method for direct preparation of 4-substituted quinazoline derivatives from a reaction between substituted 2-aminobenzophenones and thiourea in the presence of dimethyl sulfoxide (DMSO). This is a unique complementary reaction system in which thiourea undergoes thermal decomposition to form carbodiimide and hydrogen sulfide, where the former reacts with 2-aminobenzophenone to form 4-phenylquinazolin-2(1H)-imine intermediate, whilst hydrogen sulfide reacts with DMSO to give methanethiol or other sulfur-containing molecule which then functions as a complementary reducing agent to reduce 4-phenylquinazolin-2(1H)-imine intermediate into 4-phenyl-1,2-dihydroquinazolin-2-amine. Subsequently, the elimination of ammonia from 4-phenyl-1,2-dihydroquinazolin-2-amine affords substituted quinazoline derivative. This reaction usually gives quinazoline derivative as a single product arising from 2-aminobenzophenone as monitored by GC/MS analysis, along with small amount of sulfur-containing molecules such as dimethyl disulfide, dimethyl trisulfide, etc. The reaction usually completes in 4-6 hr at 160 &#186;C in small scale but may last over 24 hr when carried out in large scale. The reaction product can be easily purified by means of washing off DMSO with water followed by column chromatography or thin layer chromatography.

A protocol for facile preparation of 4-substituted quinazoline derivatives from 2-aminobenzophenones, thiourea and dimethyl sulfoxide is presented.

Preparação Facile de derivados de quinazolina 4-substituída

Reported in this paper is a very simple method for direct preparation of 4-substituted quinazoline derivatives from a reaction between substituted ...

Visualization of Ambient Mass Spectrometry with the Use of Schlieren Photography

This manuscript outlines how to visualize mass spectrometry ambient ionization sources using schlieren photography. In order to properly optimize the mass spectrometer, it is necessary to characterize and understand the physical principles of the source. Most commercial ambient ionization sources utilize jets of nitrogen, helium, or atmospheric air to facilitate the ionization of the analyte. As a consequence, schlieren photography can be used to visualize the gas streams by exploiting the differences in refractive index between the streams and ambient air for visualization in real time. The basic setup requires a camera, mirror, flashlight, and razor blade. When properly configured, a real time image of the source is observed by watching its reflection. This allows for insight into the mechanism of action in the source, and pathways to its optimization can be elucidated. Light is shed on an otherwise invisible situation.

This paper presents a protocol for the visualization of gaseous streams of an ambient ionization source using schlieren photography and mass spectrometry.

Visualização de ambiente Espectrometria de Massa com o uso da fotografia Schlieren

This manuscript outlines how to visualize mass spectrometry ambient ionization sources using schlieren photography. In order to properly optimize the mass ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

Síntese Facile de micelas Worm-like por luz visível Mediated Dispersão Polimerização Usando Photoredox Catalisador

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Direct cross-coupling between two alkenes via vinylic C-H bond activation represents an efficient strategy for the synthesis of butadienes with high atomic and step economy. However, this functionality-directed cross-coupling reaction has not been developed, as there are still limited directing groups in practical use. In particular, a stoichiometric amount of oxidant is usually required, producing a large amount of waste. Due to our interest in novel 1,3-butadiene synthesis, we describe the ruthenium-catalyzed olefination of electron-deficient alkenes using allyl acetate and without external oxidant. The reaction of 2-phenyl acrylamide and allyl acetate was chosen as a model reaction, and the desired diene product was obtained in 80% isolated yield with good stereoselectivity (Z,E/Z,Z = 88:12) under optimal conditions: [Ru(p-cymene) Cl2]2 (3 mol %) and AgSbF6 (20 mol %) in DCE at 110 &#186;C for 16 h. With the optimized catalytic conditions in hand, representative &#945;- and/or &#946;-substituted acrylamides were investigated, and all reacted smoothly, regardless of aliphatic or aromatic groups. Also, differently N-substituted acrylamides have proven to be good substrates. Moreover, we examined the reactivity of different allyl derivatives, suggesting that the chelation of acetate oxygen to the metal is crucial for the catalytic process. Deuterium-labeled experiments were also conducted to investigate the reaction mechanism. Only Z-selective H/D exchanges on acrylamide were observed, indicating a reversible cyclometalation event. In addition, a kinetic isotope effect (KIE) of 3.2 was observed in the intermolecular isotopic study, suggesting that the olefinic C-H metalation step is probably involved in the rate-determining step.

Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

The ruthenium-catalyzed olefination of electron-deficient alkenes with allyl acetate is described here. By using aminocarbonyl as a directing group, this external oxidant-free protocol has high efficiency and good stereo- and regioselectivity, opening a novel synthetic route to (Z,E)-butadiene skeletons.

Preparação Fácil de (2Z,4E)-Dienamidas pela Olefinação de Alquenos Elétron-deficientes com Acetato de Alila

Direct cross-coupling between two alkenes via vinylic C-H bond activation represents an efficient strategy for the synthesis of butadienes with high ...