Name: a simple and efficient protocol for the catalytic insertion polymerization of functional norbornenes
Uploaded: 2017-02-27T13:00:00
Description: Watch this Scientific Journal Video about A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes at JoVE.com

The authors acknowledge funding from Fonds de Recherche du Qu&#233;bec - Nature et Technologies, from Conseil Recherches en Sciences Naturelles et G&#233;nie (program INNOV) and PrimaQu&#233;bec.

1. Preparation of Poly(5-norbornene-2-carboxylic acid), PNBE(CO2H)
<ol>
	<li>Preparation of the monomer NBE(CO2H)
	<ol>
		<li>Weigh out acrylic acid (AA) (327 g, 4.5 mol, 2 eq.) and hydroquinone (4.9 g, 4.5 x 10-2 mol, 0.02 eq.) and add them to a 2 L round-bottom flask equipped with a condenser and a magnetic stir bar. Heat the flask at 150 &#176;C using a silicone oil bath.</li>
		<li>Once reflux is settled, add DCPD (300 g, 2.3 mol, 1 eq.) in a single portion, and the...

<ol>
	<li>Gaylord, N. G., Mandal, B. M., Martan, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peroxide-induced+polymerization+of+norbornene.">Peroxide-induced polymerization of norbornene.</a> J. Polym. Science, Polym. Lett. Ed. 14 (9), 555-559 (1976).</li><li>Janiak, C., Lassahn, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+vinyl+homopolymerization+of+norbornene.">The vinyl homopolymerization of norbornene.</a> Macromol. Rapid Comm. 22 (7), 479-493 (2001).</li><li>Bielawski, C. W., Grubbs, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Living+ring-opening+metathesis+polymerization.">Living ring-opening metathesis polymerization.</a> Prog. Polym. 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Appl. Polym. Sci. 120 (4), 2008-2016 (2011).</li><li>M&#252;ller, K., Jung, Y., Yoon, D. Y., Agarwal, S., Greiner, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vinyl-type+polymerization+of+alkylester-substituted+norbornenes+without+endo/exo+separation.">Vinyl-type polymerization of alkylester-substituted norbornenes without endo/exo separation.</a> Macromol. Chem. Phys. 211 (14), 1595-1601 (2010).</li><li>Boffa, L. S., Novak, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Copolymerization+of+polar+monomers+with+olefins+using+transition-metal+complexes.">Copolymerization of polar monomers with olefins using transition-metal complexes.</a> Chem. Rev. 100 (4), 1479-1494 (2000).</li><li>Funk, J. K., Andes, C. E., Sen, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Addition+Polymerization+of+Functionalized+Norbornenes:+The+Effect+of+Size+Stereochemistry,+and+Coordinating+Ability+of+the+Substituent.">Addition Polymerization of Functionalized Norbornenes: The Effect of Size Stereochemistry, and Coordinating Ability of the Substituent.</a> Organometallics. 23 (8), 1680-1683 (2004).</li><li>Hennis, A. D., Polley, J. D., 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=Novel,+efficient,+palladium-based+system+for+the+polymerization+of+norbornene+derivatives:+Scope+and+mechanism.">Novel, efficient, palladium-based system for the polymerization of norbornene derivatives: Scope and mechanism.</a> Organometallics. 20 (13), 2802-2812 (2001).</li><li>Commarieu, B., Claverie, 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=Bypassing+the+lack+of+reactivity+of+endo-substituted+norbornenes+with+the+catalytic+rectification-insertion+mechanism.">Bypassing the lack of reactivity of endo-substituted norbornenes with the catalytic rectification-insertion mechanism.</a> Chem. Sci. 6 (4), 2172-2182 (2015).</li><li>Commarieu, B., Potier, J., 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=Ultrahigh+Tg+epoxy+thermosets+based+on+insertion+polynorbornenes.">Ultrahigh Tg epoxy thermosets based on insertion polynorbornenes.</a> Macromoecules. 49 (3), 920-925 (2016).</li><li>Pirrung, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Synthetic Organic Chemist's Companion. , (2007).</li><li>Kanao, M., Otake, A., Tsuchiya, K., Ogino, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereo-selective+synthesis+of+5-norbornene-2-exo-carboxylic+acid-Rapid+isomerization+and+kinetically+selective+hydrolysis.">Stereo-selective synthesis of 5-norbornene-2-exo-carboxylic acid-Rapid isomerization and kinetically selective hydrolysis.</a> Int. J. Org. Chem. 2 (1), 26-30 (2012).</li><li>Huertas, D., Florscher, M., Dragojlovic, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solvent-free+Diels-Alder+reactions+of+in+situ+generated+cyclopentadiene.">Solvent-free Diels-Alder reactions of in situ generated cyclopentadiene.</a> Green Chem. 11 (1), 91-95 (2009).</li><li>Pierre, F., Commarieu, B., Tavares, A. C., Claverie, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+Tg+sulfonated+insertion+polynorbornene+ionomers+prepared+by+catalytic+insertion+polymerization.">High Tg sulfonated insertion polynorbornene ionomers prepared by catalytic insertion polymerization.</a> Polymer. 86, 91-97 (2016).</li><li>Woo, H. G., Li, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Advanced functional materials, Chapter 1.6.8,30. 1, (2011).</li><li>Kim, D. -. G., Bell, A., Register, R. a. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Living+vinyl+addition+polymerization+of+substituted+norbornenes+by+a+t-Bu3P-Ligated+Methylpalladium+Complex.">Living vinyl addition polymerization of substituted norbornenes by a t-Bu3P-Ligated Methylpalladium Complex.</a> ACS Macro Letters. 4 (3), 327-330 (2015).</li><li>Seung, H., S, A., Baek, K., Sang, S., Intech, S. i. l. a. g. u. i. ,. M. .. 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The method proposed here is simple, and readily amenable to scale-up. All chemicals could be used as received without any purification. Note that performing the reaction at a lower scale (e.g. scales &#8804;1 g) usually yields lower yields due to an unavoidable loss of material during the handling and the collection.
The catalysts are formed in situ upon the reaction of commercial Pd compounds with cationizing agents. In our hands, the yield of the reaction as well as the cha...

Norbornene, NBE, the Diels-Alder adduct of ethylene and cyclopentadiene (obtained by &#34;cracking&#34; of dicyclopentadiene (DCPD)), is readily polymerized using either free-radical polymerization,1 cationic polymerization,2 ring-opening metathesis polymerization3 and catalytic insertion polymerization.4,5,6,7 Unlike the other mechanisms, the catalytic insertion polymerization leads to the formation of a very high glass-transition temperature (Tg) polymer whereby the bicyclic backbone of NBE is conserved. A variety of catalysts such as metallocene catalysts and late transition metal catalysts can be used to promote the polymerization of NBE.4,5,6,7 However, due to its low solubility and due to difficulties associated with the processing of a very high Tg polymer, the PNBE homopolymer has, to our knowledge, never found any use.
Functional polynorbornenes (PNBEs) have been the object of considerable scrutiny for the last 20 years, because they combine the high Tg imparted by the bicyclic rigid repeat unit as well as desirable properties endowed by their functionalities.8,9,10 NBE monomers are obtained from rather simple and inexpensive feedstocks, using a one-step Diels-Alder reaction between cyclopentadiene and a functionalized dienophile. However, the Diels-Alder reaction leads to two stereoisomers, endo and exo, which have very different reactivities.11,12 In fact, the endo stereoisomer is less reactive than exo form and deactivates the catalyst.11,12 Thus, in the past, the preparation of functional polynorbornenes usually required the separation of the endo and exo stereoisomers, and only the exo stereoisomer was used. Such a separation procedure was time-consuming, and led to the accumulation of unreacted endo stereoisomers as undesirable waste.
Recently we have shown that the polymerization of functionalized NBEs containing both stereoisomers is in fact feasible.13 We have thus been able to prepare a variety of substituted PNBEs, containing functional groups such as esters, anhydrides, aldehydes, imides, alcohols and double bonds. Due to their high Tg and functionality, these polymers show desirable properties. We describe here two methods to prepare functional polymers. The first one leads to the synthesis of the water soluble polymer poly(5-norbornene-2-carboxylic acid), PNBE(CO2H), using a cationic Pd catalyst (Figure 1).13,14 The same polymerization method can be used to prepare functional PNBEs with various pendant functionalities, such as esters, alcohols, imides, bromo-alkyls, aldehydes and anhydrides. In our hands, this cationic Pd catalyst cannot be used for NBEs containing pendant double bonds such as 5-vinyl-2-norbornene. In this case, a partial insertion of the pendant double bond during the polymerization leads to the formation of a cross-linked material. Therefore, we present here a second method dedicated to the formation of poly(5-vinyl-2-norbornene), PNBE(vinyl), using Pd2(dba)3:AgSbF6:PPh3 as an in situ catalyst.14 The pendant vinyl groups of the polymer are then further epoxidized, to lead to the formation of PNBE(epoxy) (Figure 1). Both PNBE(CO2H) and PNBE(epoxy) have been found to lead to the formation of thermoset resins with a Tg as high as 350 &#176;C.14 Thus, the simple method described here allows one to efficiently prepare polymers with a very high Tg and having a variety of functional groups, which can be used for numerous applications.
<img alt="Figure 1" src="/files/ftp_upload/54552/54552fig1.jpg" /> 
Figure 1: Functional PNBEs prepared by Pd catalyzed polymerization. (A) preparation of PNBE(CO2H), (B) preparation of PNBE(vinyl) and PNBE(epoxy). The dashed bond indicates a mixture of endo and exo isomers. <a href="http://cloudflare.jove.com/files/ftp_upload/54552/54552fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table border="0" cellpadding="0" cellspacing="0" width="945">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">acrylic acid</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">147230</td>
			<td style="width:299px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">hydroquinone</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td>H9003</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">dicyclopendadiene</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td align="left">454338</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">palladium allyl dichloride dimer</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td>222380</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">silver hexfluoro antimonate</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">227730</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">liquid nitrogen</td>
			<td style="width:241px;">Local Facility</td>
			<td style="width:135px;">NA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">ethyl acetate</td>
			<td style="width:241px;">Fischer Scientific</td>
			<td>E14520</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">5-vinyl-2-norbornene</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">148679</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">toluene</td>
			<td style="width:241px;">Fischer Scientific</td>
			<td>T290-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">palladium dba</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">227994</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">triphenyl phosphine</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">93090</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">silica gel 40-63 microns</td>
			<td style="width:241px;">Silicycle</td>
			<td style="width:135px;">Siliaflash</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">methanol</td>
			<td style="width:241px;">Fischer Scientific</td>
			<td>BPA412-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">dichloromethane</td>
			<td style="width:241px;">EMD Millipore</td>
			<td>DX08311</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">formic acid</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">F0507</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">acetic acid</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td>320099</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:271px;">hydrogen peroxide solution</td>
			<td style="width:241px;">Sigma-Aldrich</td>
			<td style="width:135px;">216763</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:271px;">acetone</td>
			<td style="width:241px;">Fischer Scientific</td>
			<td>A18-200</td>
			<td></td>
		</tr>
	</tbody>
</table>

a simple and efficient protocol for the catalytic insertion polymerization of functional norbornenes

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic nature of the monomer is conserved. The resulting polymer, polynorbornene, has a very high glass transition temperature, Tg, and interesting optical and electrical properties. However, the polymerization of functional norbornenes by this mechanism is complicated by the fact that the endo substituted norbornene monomer has, in general, a very low reactivity. Furthermore, the separation of the endo substituted monomer from the exo monomer is a tedious task. Here, we present a simple protocol for the polymerization of substituted norbornenes (endo:exo ca. 80:20) bearing either a carboxylic acid or a pendant double bond. The process does not require that both isomers be separated, and proceeds with low catalyst loadings (0.01 to 0.02 mol%). The polymer bearing pendant double bonds can be further transformed in high yield, to afford a polymer bearing pendant epoxy groups. These simple procedures can be applied to prepare polynorbornenes with a variety of functional groups, such as esters, alcohols, imides, double bonds, carboxylic acids, bromo-alkyls, aldehydes and anhydrides.

The NBE monomers are prepared by simple Diels-Alder reaction of DCPD and a suitable dienophile, for example acrylic acid (AA). Normally, DCPD is cracked to yield cyclopentadiene (CPD) before reaction.17 Freshly cracked CPD is then engaged in the Diels-Alder reaction. However, in this protocol, both cracking and Diels-Alder steps are performed concomitantly, in a one-pot reaction. Thus, as soon as CPD is formed, it reacts with AA to yield 5-norbornene-2-carboxylic a...

Watch this Scientific Journal Video about A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes at JoVE.com

A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes

We describe the catalytic insertion polymerization of 5-norbornene-2-carboxylic acid and 5-vinyl-2-norbornene to form functional polymers with a very high glass transition temperature.

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic ...

The overall goal of this synthetic procedure is to prepare functional insertion polynorbornenes, which are highly functional polymers with a very high glass transition temperature. The main advantage of this technique is that it's possible to access high performance polymers bearing highly reactive functional groups such as epoxy groups or acid groups via a simple experimental protocol. Generally, researchers that are new to catalytic polymer synthesis will struggle because the synthesis must be performed using very high standards of purity, but here, in the process we're going to describe, the synthesis can be performed easily with no special purification step.Demonstrating part of the procedure will be Moubarak Compaore, a graduate student in the Claverie laboratory. To begin this procedure, set up a one liter round bottom flask with a condenser and stir bar. Add 327 grams of acrylic acid and 4.9 grams of hydroquinone to the flask.Then use a heating block to heat the mixture to 150 degrees Celsius. Once the refluxing has settled, add 300 grams of DCPD. Then increase the temperature to 170 degrees Celsius for 16 hours.The solution color will change from clear to yellow-brown. Using a Pasteur pipette, extract a sample. Analyze by proton NMR, using deuterated chloroform as the solvent.Next, remove the condenser from the round bottom flask. Replace it with a simple distillation setup connected to a condenser circulating cold water. Place the reaction setup under vacuum and set the pressure to one millimeter mercury.Then heat to 100 degrees Celsius for approximately one hour. Collect and discard the clear liquid that boils off. Replace the collection flask with a 250 milliliter round bottom flask.Heat to 155 degrees Celsius for seven hours to distill the NBE carboxylic acid. Analyze the distilled liquid by proton NMR to determine the purity and endo to exo proportions. Then add 300 grams of NBE carboxylic acid to a 500 milliliter round bottom flask equipped with a magnetic stir bar.Degas the NBE carboxylic acid by bubbling nitrogen for 40 minutes using a slow stirring rate for the stir bar. Add 76 milligrams of allylpalladium(II)chloride dimer. Then add 180 milligrams of silver antimonate.Increase the stirring rate and heat the solution to 70 degrees Celsius under a slight nitrogen flux for 36 hours. Next, cool the flask with liquid nitrogen. Using a spatula, break the polymer into small pieces.Add 750 milliliters of ethyl acetate to a two liter beaker equipped with a magnetic stir bar. Then add the polymer chunks under vigorous stirring. Allow the solution to continue stirring for two hours.After stirring is complete, filter the solution using a Buchner funnel equipped with filter paper. Wash the polymer with 500 milliliters of ethyl acetate three times, then dry the polymer in a vacuum oven at 50 degrees Celsius for 12 hours. Separately degas 100 grams of toluene and 100 grams of NBE(vinyl)by bubbling with nitrogen gas for 30 minutes.After that, place both in the glove box. In the glove box, add the toluene into a 250 milliliter round bottom flask. Next, successively add 76 milligrams of PD2(DBA)3, 68 milligrams of silver antimonite and 43 milligrams of triphenylphosphine to the toluene solution.Then add the degassed NBE(vinyl)and stir at 70 degrees Celsius for 72 hours. Once stirring is complete, remove the solution from the glove box and transfer it into a one liter glass bottle equipped with a magnetic stir bar. Add 200 milliliters of fresh toluene and stir.Then add 10 grams of silica powder and continue stirring at room temperature for 16 hours. After stirring is complete, let the solution settle for two hours to allow the silica particles to sedimentate. Filter the settled solution through a Buchner funnel equipped with filter paper.Rinse the silica particles with fresh toluene and filter it through the Buchner funnel. Next, add 1.2 liters of methanol to a fresh four liter beaker equipped with a magnetic stir bar. Gradually add this solution of toluene and polymer to the beaker under vigorous stirring.Continue stirring for 30 minutes. After stirring is complete, filter the polymer using a Buchner funnel and filter paper. Wash the polymer with 400 milliliters of methanol three times.Analyze the polymer purity by proton NMR to determine if the residual monomer is present. If so, perform one additional wash with methanol. After washing is complete, dry the PNBE(vinyl)under vacuum at room temperature overnight.Add 150 grams of dichloromethane to a 500 milliliter round bottom flask equipped with a magnetic stir bar and a condenser. Then add 15 grams of PNBE(vinyl)with stirring. Once the polymer has completely dissolved, place the flask in an ice bath to cool for 15 minutes.In a fresh beaker, mix 30 grams of formic acid and five grams of acetic acid. Add this acid solution to the flask and let it cool for 15 minutes. Next, add 75 grams of a 30%aqueous solution of hydrogen peroxide and stir the solution for 18 hours.After this, remove a small sample. Precipitate the polymer with acetone and analyze with proton NMR as outlined in the text protocol. If the signal for the double bond has not decreased sufficiently, continue stirring the reaction, analyzing by proton NMR hourly.Once the signal for the double bond has decreased sufficiently, add 750 milliliters of acetone to a fresh four liter beaker equipped with a magnetic stir bar. Gradually add the polymer solution under vigorous stirring. Let the solution continue to stir for 15 minutes.After that, filter the polymer using a Buchner funnel and filter paper. Wash the polymer with 200 milliliters of acetone four times. Finally, dry the polymer under vacuum at room temperature overnight.In this procedure, polymers are obtained by catalyzed polymerization and collected in the form of dry powders. Representative results for the proton NMR analysis of the polymers can be seen here. This analysis confirms the epoxidation of PNBE(vinyl)The decreasing ratio between the integrals of the vinyl group and the other protons in the PNBE(epoxy)spectrum proves the efficacy of this epoxidation procedure, with 97%of PNBE(vinyl)being converted to PNBE(epoxy)FTIR spectroscopy is also used to confirm the outcome of the epoxidation reaction.This is seen by the apparition of a characteristic peak at 875 inverse centimeters and the disappearance of the 904 inverse centimeter and 992 inverse centimeter peaks, which are observed in the PNBE(vinyl)polymer. So once mastered, an ordinary scale of either polymer, be it polynorbornene epoxy or polynorbornene acid, can be prepared in less than a week with minimal manipulation time.

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Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization

We demonstrate a method for high-throughput catalyst screening using a parallel pressure reactor starting from the initial synthesis of a nickel ...

A Protocol for the Production of Gliadin-cyanoacrylate Nanoparticles for Hydrophilic Coating

This article presents a protocol for the production of protein-based nanoparticles that changes the hydrophobic surface to hydrophilic by a simple spray ...

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 ...

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient ...

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from ...

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

We demonstrate a method for the synthesis of NixNb1-xO catalysts with sponge-like and fold-like nanostructures. By varying the Nb:Ni ratio, a series of ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...