The authors have nothing to disclose.

Caution: Please consult all relevant material safety data sheets (MSDS) before use. All cross-coupling reactions should be performed in vials under a sealed argon atmosphere (1 atm).
1. Preparation of Butadienes by the Olefination of Acrylamides with Allyl Acetate
<ol>
	<li>Dry a screw-cap vial (8 mL) with a compatible magnetic stir bar in an oven at 120 &#176;C for over 2 h. Cool the hot vial to room temperature by blowing on it with inert gas before use.</li>
	<li>Use an analytical balance and weigh 3.7 mg (~3 mol %, ~0.005 mmol) of [Ru(p-cymene)Cl2]2 (brown powder) and 13.7 mg (20 mol%, 0.04 mmol) of AgSbF6 (white solid) into the above reaction vial. 
	NOTE: Since this is a new methodology, the cross-coupling reactions have been performed on a small scale for proof of concept to reduce waste formation. AgSbF6 is used as an additive that may abstract chloride to generate a cationic ruthenium complex for electrophilic C-H bond activation13. Other silver salts, such as Ag2CO3, have also been tested, but no product was detected. The weight of the catalyst ([Ru(p-cymene)Cl2]2) is not very accurate and is in the range of 3.4-3.9 mg.</li>
	<li>Add 1 mL of dry 1,2-dichloroethane to the reaction vial. 
	NOTE: The amount of solvent is flexible-1 mL of 1,2-dichloroethane is just about enough to meet the minimal requirement of volume for the cross-coupling reaction. However, a little more (~0.1 mL) solvent is also permissible for a reaction of this scale. 1,2-dichloroethane was dried over a 3-&#550; molecular sieve before its use.</li>
	<li>Use an analytical balance and add acrylamide (0.2 mmol, 1.0 equiv; solid or oil) to the above reaction vial.</li>
	<li>Use a micro-syringe to add 43 &#181;L (0.4 mmol, 2.0 equiv) of allyl acetate (a colorless liquid) to the above reaction vial. 
	NOTE: Here, an excess amount of allyl acetate is required to inhibit the homo-coupling of acrylamide and to ensure that the acrylamide is fully converted. The product yield decreases if less allyl acetate (1.5 equiv) is added. The addition of more allyl acetate (3.0 equiv) cannot further improve the yield. In practice, there is no observed homo-coupling of allyl acetate, and the residual allyl acetate could be recovered.</li>
	<li>Gently blow on the reaction vial with argon gas and cover the vial with a compatible screw-cap as quickly as possible. 
	NOTE: The vial should be covered with a screw-cap as quickly as possible because an inert atmosphere is crucial for the cross-coupling reaction. It is better to perform the above protocol in a glove box.</li>
	<li>Stir the reaction mixture at room temperature for an additional 5 min.</li>
	<li>Heat the reaction vial to 110 &#176;C in an oil bath with stirring for 16-18 h. 
	NOTE: Generally, a color change to dark red is an indication that the reaction is taking place.</li>
	<li>After cooling the vial down, use ethyl acetate:petroleum ether (2:1 or 1:3) mixtures as the solvent to develop the thin layer chromatography (TLC) plates to monitor the progress of the reaction by comparing the mixture to an acrylamide standard. 
	NOTE: Depending upon the nature of the starting materials, the reaction may not go to completion. Typical Rf values of the products and starting materials are in the range of 0.3 - 0.7. The acrylamide starting material has been observed as a lower running spot than the butadiene product.</li>
	<li>Dissolve the crude product in a minimum of DCM and load it onto a silica column wet with petroleum ether. Separate the cross-coupling product via column chromatography using a mixture of ethyl acetate:petroleum ether (1:100 to 1:4) as the eluent.
	<ol>
		<li>Collect the eluent in a separate flask, evaporate the solvent on a rotatory evaporator, and place it under a high vacuum for a minimum of 2 h.</li>
		<li>Obtain approximately 20-50 mg of product for characterization by NMR spectroscopy. 
		NOTE: The reaction mixture should be applied to column chromatography for purification directly after reaction completion.</li>
	</ol>
	</li>
</ol>
2. Characterization of Dienamides
<ol>
	<li>.Characterize and assess the purity of the final product using 1H and 13C NMR spectroscopy14. Typically, the chemical shift of the carbonyl carbon appears near 170 ppm on the 13C NMR spectrum. The three sp2 protons of the butadiene functional group are represented by characteristic peaks near 6.0 and 5.6 ppm.</li>
	<li>Use infrared spectroscopy14 to identify the characteristic carbonyl and C-C double-bond peak of the diene product.</li>
	<li>Determine the molecular mass of the product and further validate the identity using high-resolution mass spectrometry (HRMS)14.</li>
	<li>Determine the melting point of the solid products14.</li>
</ol>

<ol>
	<li>Negishi, E., 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=Recent+Advances+in+Efficient+and+Selective+Synthesis+of+Di-,+Tri-,+and+Tetrasubstituted+Alkenes+via+Pd-Catalyzed+Alkenylation-Carbonyl+Olefination+Synergy.">Recent Advances in Efficient and Selective Synthesis of Di-, Tri-, and Tetrasubstituted Alkenes via Pd-Catalyzed Alkenylation-Carbonyl Olefination Synergy.</a> Acc Chem Res. 41 (11), 1474-1485 (2008).</li><li>Maryanoff, B. E., Reitz, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Wittig+olefination+reaction+and+modifications+involving+phosphoryl-stabilized+carbanions.+Stereochemistry,+mechanism,+and+selected+synthetic+aspects.">The Wittig olefination reaction and modifications involving phosphoryl-stabilized carbanions. Stereochemistry, mechanism, and selected synthetic aspects.</a> Chem Rev. 89 (4), 863-927 (1989).</li><li>Stille, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Palladium-Catalyzed+Cross-Coupling+Reactions+of+Organotin+Reagents+with+Organic+Electrophiles.">The Palladium-Catalyzed Cross-Coupling Reactions of Organotin Reagents with Organic Electrophiles.</a> Angew Chem Int Ed. 25 (6), 508-524 (1986).</li><li>Zhang, Y., Cui, Z., Li, Z., Liu, Z. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pd(II)-Catalyzed+Dehydrogenative+Olefination+of+Vinylic+C-H+Bonds+with+Allylic+Esters:+General+and+Selective+Access+to+Linear+1,3-Butadienes.">Pd(II)-Catalyzed Dehydrogenative Olefination of Vinylic C-H Bonds with Allylic Esters: General and Selective Access to Linear 1,3-Butadienes.</a> Org Lett. 14 (7), 1838-1841 (2012).</li><li>Shang, X., Liu, Z. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transition+metal-catalyzed+Cvinyl-Cvinyl+bond+formation+via+double+Cvinyl-H+bond+activation.">Transition metal-catalyzed Cvinyl-Cvinyl bond formation via double Cvinyl-H bond activation.</a> Chem Soc Rev. 42 (8), 3253-3260 (2013).</li><li>Hu, X. H., Yang, X. F., Loh, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+Alkenylation+and+Hydroalkenylation+of+Enol+Phosphates+through+Direct+C-H+Functionalization.">Selective Alkenylation and Hydroalkenylation of Enol Phosphates through Direct C-H Functionalization.</a> Angew Chem Int Ed. 54 (51), 15535-15539 (2015).</li><li>Kong, L., 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=Cobalt+(III)-Catalyzed+C-C+Coupling+of+Arenes+with+7-Oxabenzonorbornadiene+and+2-Vinyloxirane+via+C-H+Activation.">Cobalt (III)-Catalyzed C-C Coupling of Arenes with 7-Oxabenzonorbornadiene and 2-Vinyloxirane via C-H Activation.</a> Org Lett. 18 (15), 3802-3805 (2016).</li><li>Feng, C., Feng, D., Loh, T. 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N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Uniting+C1-Ammonium+Enolates+and+Transition+Metal+Electrophiles+via+Cooperative+Catalysis:+The+Direct+Asymmetric+&#945;-Allylation+of+Aryl+Acetic+Acid+Esters.">Uniting C1-Ammonium Enolates and Transition Metal Electrophiles via Cooperative Catalysis: The Direct Asymmetric &#945;-Allylation of Aryl Acetic Acid Esters.</a> J Am Chem Soc. 138 (16), 5214-5217 (2016).</li><li>Zell, D., Bu, Q., Feldt, M., Ackermann, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mild+C-H/C-C+Activation+by+Z-Selective+Cobalt+Catalysis.">Mild C-H/C-C Activation by Z-Selective Cobalt Catalysis.</a> Angew Chem Int Ed. 55 (26), 7408-7412 (2016).</li><li>Li, 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=N-Acyl+Amino+Acid+Ligands+for+Ruthenium(II)-Catalyzed+meta-C-H+tert-Alkylation+with+Removable+Auxiliaries.">N-Acyl Amino Acid Ligands for Ruthenium(II)-Catalyzed meta-C-H tert-Alkylation with Removable Auxiliaries.</a> J Am Chem Soc. 137 (43), 13894-13901 (2015).</li><li>Li, F., Yu, C., Zhang, J., Zhong, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Olefination+of+Electron-Deficient+Alkenes+with+Allyl+Acetate:+Stereo-+and+Regioselective+Access+to+(2Z,4E)-Dienamides.">Olefination of Electron-Deficient Alkenes with Allyl Acetate: Stereo- and Regioselective Access to (2Z,4E)-Dienamides.</a> Org Lett. 18 (18), 4582-4585 (2016).</li><li>Lehman, 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=.">.</a> The student's lab companion: laboratory techniques for organic chemistry: standard scale and microscale. , (2008).</li></ol>

We gratefully acknowledge National Natural Science Foundation of China (NSFC) (Nos. 21502037, 21373073, and 21672048), the Natural Science Foundation of Zhejiang Province (ZJNSF) (No. LY15B020008), the PCSIRT (No. IRT 1231), and Hangzhou Normal University for financial support. G. Z. acknowledges a Qianjiang Scholar award from Zhejiang Province, China.

[Ru(p-cymene)Cl2]2 is a cheap, easily accessible, air-stable, and highly active Ru-based catalyst with excellent functional group tolerance that efficiently operates under mild reaction conditions to give C-H/C-H coupling butadiene products. Silver salt AgSbF6 was used as an additive that may abstract the chloride of [Ru(p-cymene)Cl2]2 to generate a cationic ruthenium complex for the following C-H bond activation. However, only &#945;-subst...

Butadienes are widely occurring and are commonly found in many natural products, drugs, and bioactive molecules1. Chemists have made intense efforts to develop an efficient, selective, and practical synthetic methodology for the synthesis of 1,3-butadienes2,3. Recently, direct cross-couplings between two alkenes via double vinylic C-H bond activation was developed, representing an efficient strategy for the synthesis of butadienes, with high atomic and step economy. Among them, the palladium-catalyzed cross-coupling of two alkenes has attracted much attention, providing (E,E)-configured butadienes via alkenyl-Pd species4,5. For example, Liu&#39;s group developed a Pd-catalyzed butadiene synthesis by the direct cross-coupling of alkenes and allyl acetate (Figure 1 and Equation 3)4. Meanwhile, the functional group-directed cross-coupling between alkenes provided butadienes with excellent (Z,E)-stereoselectivity due to the olefinic C-H cyclometalation event, representing a complementary method6. To date, some directing groups, such as enolates, amides, esters, and phosphates, have been successfully introduced to the cross-coupling between alkenes, providing a series of valuable and functionalized 1,3-butadienes. However, the 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 to maintain the catalytic cycle, which produces a large amount of organic and inorganic wastes. There are very limited examples using electron-rich alkenes as the coupling partner.
Allyl acetate and its derivatives have been deeply investigated in organic transformations as powerful allylation and olefination reagents, including catalyzed cross-coupling, Friedel-Crafts allylation of electron-rich arenes, and catalytic C-H activation of electron-deficient arenes (Figure 1 and Equation 1)7. More recently, the Loh group developed a rhodium(III)-catalyzed C-H allylation of electron-deficient alkenes with allyl acetates, creating 1,4-dienes (Figure 1 and Equation 2)8. Meanwhile, the Kanai group reported a dehydrative direct C-H allylation with allylic alcohols by using a Co(III) catalyst9. Interestingly, Snaddon and co-workers disclosed a novel cooperative catalysis-based method for the direct asymmetric &#945;-allylation of acyclic esters10. Very recently, the Ackermann group reported several novel allylation examples using inexpensive Fe, Co, and Mn catalysts11. These reports have made breakthroughs in allylation and olefination reactions, but double-bond migration and poor regioselectivity are usually inevitable and are not easily controlled. Hence, developing more efficient and selective reaction patterns of allyl acetates to construct valuable molecules is still highly desirable. With our interest in novel 1,3-butadiene synthesis via C-H olefination, we assumed that allyl acetate could be introduced to the directed allylation of electron-deficient alkenes, first delivering 1,4-diene. Then, the more thermodynamically stable 1,3-butadiene could be formed after the migratory isomerization of the C-C double bond7, forming the diene product that cannot be obtained by cross-coupling using electron-rich alkenes, such as propene, as coupling partner6. Here, we report an inexpensive Ru(III)-catalyzed olefinic C-H bond olefination of acrylamides with allyl acetates in the absence of any oxidant, which opens a novel synthetic route for the creation of (Z,E)-butadienes (Figure 1 and Equation 4)13.

<table border="0" cellpadding="0" cellspacing="0" width="887">
	<tbody>
		<tr height="19">
			<td height="19" style="height:19px;width:284px;">Allyl Acetate</td>
			<td style="width:100px;">TCI</td>
			<td style="width:148px;">A0020</td>
			<td style="width:355px;">&#62; 98.0%(GC), 25 mL package</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:38px;width:284px;">Dichloro(p-cymene)ruthenium(II) dimer</td>
			<td style="width:100px;">TCI</td>
			<td style="width:148px;">D2751</td>
			<td>&#62; 95.0%(T), 5 g package</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Silver hexafluoroantimonate</td>
			<td style="width:100px;">TCI</td>
			<td style="width:148px;">S0463</td>
			<td>&#62; 97.0%(T),&#160; 5 g package</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">1,2-Dichloroethane</td>
			<td style="width:100px;">TCI</td>
			<td style="width:148px;">D0364</td>
			<td>&#62; 99.5%(GC), 500 g package</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Rotavapor</td>
			<td style="width:100px;">EYELA</td>
			<td style="width:148px;">N-1200A</td>
			<td>Use to dry solvent</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;width:284px;">Silica gel</td>
			<td style="width:100px;">Merck</td>
			<td style="width:148px;">107734</td>
			<td>Silica gel 60 (0.063-0.2 mm), for column chromatoraphy</td>
		</tr>
	</tbody>
</table>

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.

Our efforts were focused on the preparation of 1,3-butadiene from acrylamide and allyl acetate.
Table 1 illustrates the optimization of conditions, including the screening of various additives and solvents, using [Ru(p-cymene)Cl2]2 as the catalyst. After screening a series of representative solvents, we were pleased to find that the product yield dramatically improved to 80%, with ...

Watch this Scientific Journal Video about Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate at JoVE.com

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.

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 ...

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7.3K Views.  Hangzhou Normal University. 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.

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

Formation of Ordered Biomolecular Structures by the Self-assembly of Short Peptides

In nature, complex functional structures are formed by the self-assembly of biomolecules under mild conditions. Understanding the forces that control self-assembly and mimicking this process in vitro will bring about major advances in the areas of materials science and nanotechnology. Among the available biological building blocks, peptides have several advantages as they present substantial diversity, their synthesis in large scale is straightforward, and they can easily be modified with biological and chemical entities1,2. Several classes of designed peptides such as cyclic peptides, amphiphile peptides and peptide-conjugates self-assemble into ordered structures in solution. Homoaromatic dipeptides, are a class of short self-assembled peptides that contain all the molecular information needed to form ordered structures such as nanotubes, spheres and fibrils3-8. A large variety of these peptides is commercially available.
This paper presents a procedure that leads to the formation of ordered structures by the self-assembly of homoaromatic peptides. The protocol requires only commercial reagents and basic laboratory equipment. In addition, the paper describes some of the methods available for the characterization of peptide-based assemblies. These methods include electron and atomic force microscopy and Fourier-Transform Infrared Spectroscopy (FT-IR). Moreover, the manuscript demonstrates the blending of peptides (coassembly) and the formation of a &#34;beads on a string&#34;-like structure by this process.9 The protocols presented here can be adapted to other classes of peptides or biological building blocks and can potentially lead to the discovery of new peptide-based structures and to better control of their assembly.

This paper describes the formation of highly ordered peptide-based structures by the spontaneous process of self-assembly. The method utilizes commercially available peptides and common lab equipment. This technique can be applied to a large variety of peptides and may lead to the discovery of new peptide-based assemblies.

In nature, complex functional structures are formed by the self-assembly of biomolecules under mild conditions. Understanding the forces that control ...

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.

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

Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process.
The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

A procedure for the preparation of porous hybrid separation media composed of a macroporous polymer monolith internally coated by a high surface area microporous coordination polymer is presented.

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous ...

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.

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

A Study of the Complexation of Mercury(II) with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry

In this study we evaluated a method for the characterization of complexes, formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptide, by electrospray ionization orbitrap mass spectrometry. This strategy is based on previous successful characterization of mercury-dicysteinyl complexes involving tripeptides by utilizing mass spectrometry among other techniques. Mercury(II) chloride and a dicysteinyl tetrapeptide were incubated in a degassed buffered medium at varying stoichiometric ratios. The complexes formed were subsequently analyzed on an electrospray mass spectrometer consisting of a hybrid linear ion- and orbi- trap mass analyzer. The electrospray ionization mass spectrometry (ESI-MS) spectra were acquired in the positive mode and the observed peaks were then analyzed for distinct mercury isotopic distribution patterns and associated monoisotopic peak. This work demonstrates that an accurate stoichiometry of mercury and peptide in the complexes formed under specified electrospray ionization conditions can be determined by using high resolution ESI MS based on distinct mercury isotopic distribution patterns.

A Study of the Complexation of MercuryII with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry

The characterization of complexes formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptides by electrospray ionization orbitrap mass spectrometry is presented.

In this study we evaluated a method for the characterization of complexes, formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptide, ...

Preparation of Macroporous Epitaxial Quartz Films on Silicon by Chemical Solution Deposition

This work describes the detailed protocol for preparing piezoelectric macroporous epitaxial quartz films on silicon(100) substrates. This is a three-step process based on the preparation of a sol in a one-pot synthesis which is followed by the deposition of a gel film on Si(100) substrates by evaporation induced self-assembly using the dip-coating technique and ends with a thermal treatment of the material to induce the gel crystallization and the growth of the quartz film. The formation of a silica gel is based on the reaction of a tetraethyl orthosilicate and water, catalyzed by HCl, in ethanol. However, the solution contains two additional components that are essential for preparing mesoporous epitaxial quartz films from these silica gels dip-coated on Si. Alkaline earth ions, like Sr2+ act as glass melting agents that facilitate the crystallization of silica and in combination with cetyl trimethylammonium bromide (CTAB) amphiphilic template form a phase separation responsible of the macroporosity of the films. The good matching between the quartz and silicon cell parameters is also essential in the stabilization of quartz over other SiO2 polymorphs and is at the origin of the epitaxial growth.

A protocol is presented for the preparation of piezoelectric macroporous epitaxial films of quartz on silicon by solution chemistry using dip-coating and thermal treatments in air.

This work describes the detailed protocol for preparing piezoelectric macroporous epitaxial quartz films on silicon(100) substrates. This is a three-step ...

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.

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

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.

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

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, 1,4-benzene-bis(iminoguanidinium) (BBIG), is demonstrated. The ligand is synthesized as the chloride salt (BBIG-Cl) by in situ imine condensation of terephthalaldehyde with aminoguanidinium chloride in water, followed by crystallization as the sulfate salt (BBIG-SO4). Alternatively, BBIG-Cl is synthesized ex situ in larger scale from ethanol. The sulfate separation ability of the BBIG ligand is demonstrated by selective and quantitative crystallization of sulfate from seawater. The ligand can be recycled by neutralization of BBIG-SO4 with aqueous NaOH and crystallization of the neutral bis-iminoguanidine, which can be converted back into BBIG-Cl with aqueous HCl and reused in another separation cycle. Finally, 35S-labeled sulfate and &#946; liquid scintillation counting are employed for monitoring the sulfate concentration in solution. Overall, this protocol will instruct the user in the necessary skills to synthesize a ligand, employ it in the selective crystallization of sulfate from aqueous solutions, and quantify the separation efficiency.

A protocol for in situ aqueous synthesis of a bis(iminoguanidinium) ligand and its utilization in selective separation of sulfate is presented.

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, ...

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

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 of aqueous aluminum salts is known to produce a wide array of products with a wide range of size distributions, a variety of state-of-the-art instruments (i.e., 27Al/1H NMR, FTIR, ICP-OES, TEM-EDX, XPS, XRD, and BET) were used to characterize the synthesis products and identification of byproducts. The product, which was comprised of nanoparticles (10-30 nm), was isolated using gel permeation chromatography (GPC) column technique. Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) identified the purified material as the gibbsite polymorph of aluminum hydroxide. The addition of inorganic salts (e.g., NaCl) induced electrostatic destabilization of the suspension, thereby agglomerating the nanoparticles to yield Al(OH)3 precipitate with large particle sizes. By utilizing the novel synthetic method described here, Al(OH)3 was partially loaded inside the highly ordered mesoporous framework of MCM-41, with average pore dimensions of 2.7 nm, producing an aluminosilicate material with both octahedral and tetrahedral Al (Oh/Td = 1.4). The total Al content, measured using energy-dispersive X-ray spectrometry (EDX), was 11% w/w with a Si/Al molar ratio of 2.9. A comparison of bulk EDX with surface X-ray photoelectron spectroscopy (XPS) elemental analysis provided insight into the distribution of Al within the aluminosilicate material. Furthermore, a higher ratio of Si/Al was observed on the external surface (3.6) as compared to the bulk (2.9). Approximations of O/Al ratios suggest a higher concentration of Al(O)3 and Al(O)4 groups near the core and external surface, respectively. The newly developed synthesis of Al-MCM-41 yields a relatively high Al content while maintaining the integrity of the ordered silica framework and can be used for applications where hydrated or anhydrous Al2O3 nanoparticles are advantageous.

An ultrafine aluminum hydroxide nanoparticle suspension was prepared via the controlled titration of [Al(H2O)]3+ with L-arginine to pH 4.6 with and without cage-effect confinement within mesoporous channels of MCM-41.

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 ...