RAF ringrazia la National Science Foundation (CHE-0844946) per il supporto di questo lavoro.

1. Sintesi di SMI 2 (0,1 M) <ol><li> Fiamma asciugare da 50 ml a fondo rotondo pallone ea filo con argon. Aggiungere una barra di agitazione e coprire il pallone con setti. Pesare samario in metallo (0,2 g, 1.3 mmol) e aggiungere al pallone, il pallone di nuovo lavaggio con argon. </li><li> Aggiungere 10 ml secco, accuratamente degasata tetraidrofurano (THF), seguita da cristalli di iodio (0,254 g, 2,0 mmol). Aggiungere un palloncino argon attraverso il setto, ciò mantiene una pressione positiva di atmosfera di Ar sulla reazione. </li><li> Agitare vigorosamente la soluzione a temperatura ambiente per più di 3 ore. Come SMI 2 viene generata la soluzione passa attraverso una serie di variazioni di colore arancio, seguito dal giallo (45 min), e verde (1 ora), che alla fine si trasforma in blu. </li><li> La finale navy colore blu indica che è ionizzato samario si è formata. Al fine di garantire completa conversione, agitare la soluzione per almeno 3 ore prima di utilizzare SMI 2 in sintesi. </li></ol> 2. SaMarium Barbier-reazione esametilfosforammide (HMPA) aggiunta <ol><li> Per rendere il 2-HMPA SMI complesso, prendere l&#39;preparata sotto argon SMI 2 (10 ml, 0,1 M, 1,0 mmol) e aggiungere 1,75 ml di HMPA (10 equiv., 10 mmoli) mediante una siringa, goccia a goccia, sotto argon. Si forma un profondo colore porpora. </li><li> Separatamente in un ambiente pulito, asciutto fiala sotto argon, add iodododecane (0,45 mmol, 110 microlitri), 3-pentanone (0,45 mmol, 48 microlitri) e 2 ml di THF secco. </li><li> Aggiungere la miscela di soluzione di substrato goccia a goccia alla 2 / HMPA complesso smi. </li><li> Entro 5 minuti di agitazione, il colore viola inizierà ad apparire opaca, che indica la fine della reazione. </li><li> Dopo che la reazione è completa, la soluzione esporre all&#39;aria a spegnerlo; upon mescolando i cambiamenti di colore giallo ulteriori. </li><li> La reazione viene quindi lavorata mediante lavaggio con cloruro di ammonio acquoso saturo. Aggiungere la soluzione in un imbuto separatore e aggiungere dietiletere (5 ml). Dopo agitazione vigorosa rimuoverelo strato superiore organico, aggiungere più dietiletere. Estrarre dallo strato acquoso altre due volte e quindi combinare tutti gli strati organici. </li><li> Lavare la fase organica con una soluzione satura di tiosolfato di sodio acquoso. Rimuovere lo strato inferiore acquoso, seguito da lavaggio con acqua e lavaggio finale con soluzione salina. Ottenere lo strato superiore organico e aggiungere solfato di magnesio per assorbire qualsiasi quantità di acqua presente ultima nella soluzione. </li><li> Filtrare la soluzione attraverso un tappo di Florisil al fine di rimuovere l&#39;eccesso HMPA. </li><li> Concentrare la soluzione su un evaporatore rotativo per ottenere Barbier prodotto. Il prodotto è stato identificato da GCMS e 1 H NMR. 23 </li></ol> 3. Barbier samario di reazione-Ni (ACAC) 2 Catalyst <ol><li> Pesare Ni (ACAC) 2 (1% mol, 0,01 mmol, 0,0026 g) e aggiungere ad un ambiente pulito, asciutto fiala contenente 3 ml di THF degasata, sotto argon. Aggiungere l&#39;(acac) 2 Ni soluzione attraverso una siringa ad una s preparataoluzione di 0,1 M SMI 2 (1,0 mmol, 10 ml). </li><li> Separatamente in un ambiente pulito, asciutto fiala sotto argon, add iodododecane (0,45 mmol, 110 microlitri), 3-pentanone (0,45 mmol, 48 microlitri) e 2 ml di THF secco. </li><li> Aggiungere la soluzione di substrato goccia a goccia alla SMI 2 / miscela Ni. </li><li> Entro quindici minuti di agitazione, il colore blu dissipare per formare un colore giallo-verde che indica la fine della reazione. </li><li> Dopo che la reazione è completa, la soluzione esporre all&#39;aria a spegnerlo; upon mescolando i cambiamenti di colore giallo ulteriori. Lavorare la reazione lavando con 0,1 M aq. Acido cloridrico (3 ml). Aggiungere la soluzione in un imbuto separatore e aggiungere dietiletere (5 ml). </li><li> Lava lo strato organico usando il protocollo descritto in precedenza, con una soluzione acquosa di tiosolfato di sodio, acqua e salamoia, quindi essiccare su solfato di magnesio. Concentrare la soluzione per ottenere Barbier prodotto. Il prodotto può essere identificato mediante GCMS e 1 H NMR. 28 </sup&gt; </li></ol>

<ol>
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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemical+investigation+of+the+reducing+power+of+SmI2+in+THF+and+the+effect+of+HMPA+cosolvent.">Electrochemical investigation of the reducing power of SmI2 in THF and the effect of HMPA cosolvent.</a> Tetrahedron Lett. 38, 1137-1140 (1997).</li><li>Enenaerke, R. J., Hertz, T., Skrydstrup, T., Daasbjerg, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+ionic+samarium(II)+species+in+THF/HMPA+solution+and+investigation+of+Their+electron-donating+properties.">Evidence for ionic samarium(II) species in THF/HMPA solution and investigation of Their electron-donating properties.</a> Chem. Eur. 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Nessun conflitto di interessi dichiarati.

Una procedura semplice per generare SMI 2 soluzione e la sua applicazione nella sintesi organica utilizzando due degli additivi più comuni è presentato qui. I due esempi descritti rappresentare l&#39;importanza della comprensione meccanicistica della reazione per ottimizzare la reattività di SMI 2. Conoscenza del sostegno da parte del meccanismo di reazione consente l&#39;utilizzo di questo reagente essere adattato da chimici sintetici secondo le esigenze della loro reazione. Questo singolo elettrone riducente omogenea è facile da maneggiare e possono essere acquistati da fonti commerciali. Mentre il protocollo sopra è semplice se fatto in condizioni inerti, alcune delle procedure di risoluzione dei problemi comuni sono: (a) verificare che il THF è adeguatamente degasata e secca, (b) se metallo Sm ha avuto una prolungata esposizione all&#39;aria potrebbe avere un ossidato strato esterno, macinare il metallo con un mortaio e pestal per esporre la superficie metallica pulita, (c)fiamma asciugare la vetreria e fresco sotto argon, (d) argon è preferito atmosfera inerte su azoto, come la successiva ha dimostrato di interagire con il metallo, (e) La presenza di eccesso Sm-metallo aiuta a mantenere la concentrazione di SMI 2, (f) resublime i cristalli di iodio.

<table border="1"><tbody><tr><td> Nome del reagente </td><td> Azienda </td><td> Numero di catalogo </td><td> Commenti (opzionale) </td></tr><tr><td> Samario metallo </td><td> Acros </td><td> 29478-0100 </td><td> Maglia -40, 99,9% (su base metalli) </td></tr><tr><td> THF </td><td> OmniSolv </td><td> TX0282-1 </td><td> Purificata attraverso innovativo sistema di purificazione Technologies solvente. In alternativa può essere degassata mediante free-pompa-disgelo metodo </td></tr><tr><td> Iodio </td><td> Alfa Aesar </td><td> 41955-22 </td><td> Cristalli Resublimed, 99,8% </td></tr><tr><td> Iodododecane </td><td> Acros </td><td> 25009-0250 </td><td> 98% </td></tr><tr><td> 3-pentanone </td><td> Alfa Aesar </td><td> AAA15297-AE </td><td> 99% </td></tr><tr><td> HMPA </td><td> Alderich </td><td> H11602 </td><td> 98%, Distillare da CaO in Argon </td></tr><tr><td> Nii 2 </td><td> Alfa Aesar </td><td> 22893 </td><td> 99,5% (su base metalli) </td></tr></tbody></table>

preparation and use of samarium diiodide (smi2) in organic synthesis: the mechanistic role of hmpa and ni(ii) salts in the samarium barbier reaction

Anche se inizialmente considerato un reagente esoterico, SMI 2 è diventato uno strumento comune per i chimici organici sintetici. SMI 2 viene generata mediante l&#39;aggiunta di iodio molecolare di samario metallico in THF. 1,2-3 È un riducente delicato e selettivo singolo elettrone e la sua versatilità è il risultato della sua capacità di avviare una vasta gamma di riduzioni comprese legame CC- formatura e cascata o reazioni sequenziali. SMI 2 può ridurre una varietà di gruppi funzionali inclusi solfossidi e solfoni, ossidi di fosfina, epossidi, alogenuri alchilici ed arilici, carbonili, e doppi legami coniugati. 2-12 Una delle caratteristiche affascinanti Smi-2-mediate reazioni è la capacità di manipolare il risultato di reazioni attraverso l&#39;uso selettivo di cosolventi o additivi. Nella maggior parte dei casi, gli additivi sono essenziali nel controllo del tasso di riduzione e le reazioni chemio-o stereoselettività. 13-14 additivi commonly utilizzato per ottimizzare la reattività di SMI 2 possono essere classificati in tre gruppi principali: (1) basi di Lewis (HMPA, altri donatori di elettroni leganti chelanti, eteri, ecc), (2) fonti protonica (alcoli, acqua, ecc ), e (3) additivi inorganici (Ni (acac) 2, FeCl 3, etc). 3 Comprendere il meccanismo di SMI 2 reazioni e il ruolo degli additivi permette l&#39;utilizzo di tutte le potenzialità del reagente nella sintesi organica. La Sm-Barbier reazione viene scelta per illustrare l&#39;importanza sintetica e ruolo meccanicistico di due additivi comuni: HMPA e Ni (II) in questa reazione. La Sm-Barbier reazione è simile alla reazione di Grignard tradizionale con l&#39;unica differenza che l&#39;alogenuro alchilico, carbonile, e riducente Sm sono miscelati simultaneamente in una pentola. 1,15 Esempi di Sm reazioni mediate Barbier con una serie di partner di accoppiamento Sono stati riportati, 1,3,7,10,12 e sono stati utilized in fasi chiave della sintesi di grandi prodotti naturali. 16,17 Precedenti studi sugli effetti di additivi su SMI due reazioni hanno dimostrato che HMPA aumenta il potenziale di riduzione di SMI 2 coordinando al metallo samario centro, producendo un più potente, 13-14,18 stericamente ingombro riducente 19-21 e in alcuni casi, che svolgono un ruolo fondamentale nel post-elettronico di trasferimento di facilitare i passaggi successivi legame che formano gli eventi. 22 Nella Sm-Barbier reazione, HMPA ha dimostrato di attivare ulteriormente l&#39;alogenuro alchilico formando un complesso in una fase di pre-equilibrio. 23 Ni (II) sali sono un additivo catalitico utilizzato frequentemente in Sm-mediata trasformazioni. Anche se fondamentale per il successo 24-27, il ruolo meccanicistico di Ni (II) non era conosciuto in queste reazioni. Recentemente è stato dimostrato che SMI 2 riduce Ni (II) di Ni (0), e la reazione viene effettuata mediante organomenon metalliche Ni (0) chimica 28. Questi studi meccanicistici sottolineare che anche se il prodotto è ottenuto Barbier stessa, l&#39;uso di additivi diversi nella reazione 2 SMI altera drasticamente il percorso meccanicistica della reazione. Il protocollo per l&#39;esecuzione di questi SMI 2-avviate reazioni è descritto.

La figura 1 illustra la reazione samario Barbier. Senza additivi la Sm-mediata reazione avviene 72 ore, ottenendo 69% del prodotto desiderato con i rimanenti essendo materiali di partenza. Con l&#39;aggiunta di 10 o più equiv. HMPA di reazione è quasi quantitativa e completa in pochi minuti. 15,23 Con l&#39;aggiunta di 1% molare Ni (acac) 2, la reazione è completa in 15 min, con una resa del 97%. 28 Quando HMPA si aggiunge alla SMI 2, le sposta cosolvente il THF coordinato per formare SMI 2 - (HMPA) 4. Con l&#39;aggiunta di ancora più HMPA (6-10 equiv.), Gli ioni ioduro sono spostati alla sfera esterna (Figura 2). 19-21 studi meccanicistici indicano che quando HMPA viene utilizzato nel Sm-Barbier reazione del cosolvente interagisce anche con il substrato formando un alogenuro alchilico complesso che allunga il legame carbonio-alogenuro, attivando il species rendendola più soggetta a riduzione Sm (Figura 3). Attraverso questa comprensione dettagliata dei ruoli di HMPA, un meccanismo per la Sm-Barbier reazione con HMPA stato proposto (Figura 4). 23 L&#39;alogenuro alchilico-HMPA complesso formato in un pre-equilibrio passo è ridotta Sm / HMPA per formare l&#39; radicale lo stadio cineticamente. Il radicale subisce ulteriore riduzione per formare una specie organosamarium che si accoppia con il carbonile e su protonazione rese il prodotto finale. Nel caso di Ni (II) additivo, SMI 2 riduce inizialmente Ni (II) al Ni (0) preferenzialmente rispetto alla riduzione di uno dei substrati. Sulla base di studi cinetici e meccanicistici il seguente meccanismo è stato proposto (Figura 5) 28. Dopo la riduzione da SMI 2, il Ni solubile (0) inserisce nella specie il legame alogenuro alchilico formando una specie organonickel. Spinto dalla natura altamente oxophilic di Sm (III)<html> , Transmetallazione per formare un intermedio organosamarium comunicati Ni (II) nel ciclo catalitico. Il organosamarium poi coppia con il carbonile, e su protonazione costituisce l&#39;alcool desiderato terziario. È stato anche osservato che Ni (0) nanoparticelle sono formate attraverso Sm-mediata riduzione di Ni (II), tuttavia queste particelle sono risultati essere inattivi e la fonte di disattivazione del catalizzatore. <img alt="Figura 1" fo:content-width="4in" fo:src="/files/ftp_upload/4323/4323fig1highres.jpg" src="/files/ftp_upload/4323/4323fig1.jpg" /> Figura 1. Samario reazione Barbier con iodododecane e 3-pentanone. <img alt="Figura 2" fo:content-width="4in" fo:src="/files/ftp_upload/4323/4323fig2highres.jpg" src="/files/ftp_upload/4323/4323fig2.jpg" /> Figura 2. SMI 2-HMPA complesso. ONTENUTO &quot;fo: keep-together.within-page =&quot; always &quot;&gt; <img alt="Figura 3" fo:content-width="3.5in" fo:src="/files/ftp_upload/4323/4323fig3highres.jpg" src="/files/ftp_upload/4323/4323fig3.jpg" /> Figura 3. HMPA e complesso ioduro di alchile. <img alt="Figura 4" fo:content-width="4.5in" fo:src="/files/ftp_upload/4323/4323fig4highres.jpg" src="/files/ftp_upload/4323/4323fig4.jpg" /> Figura 4. Meccanismo proposto per la reazione samario Barbier con HMPA eccesso. <img alt="Figura 5" fo:content-width="4in" fo:src="/files/ftp_upload/4323/4323fig5highres.jpg" src="/files/ftp_upload/4323/4323fig5.jpg" /> Figura 5. Meccanismo proposto per la reazione di samario Barbier catalitico contenente Ni (II).

Watch this Scientific Journal Video about Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction at JoVE.com

Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction

Una procedura semplice per la preparazione di samario diioduro (SMI<sub&gt; 2</sub&gt;) In THF viene descritto. Il ruolo dei due principali additivi cioè esametilfosforammide (HMPA) e Ni (acac)<sub&gt; 2</sub&gt; In Sm reazioni mediate è dimostrato nella Sm-Barbier reazione.

Preparazione ed uso di samario diioduro (SMI<sub&gt; 2</sub&gt;) Nella sintesi organica: il ruolo meccanicistico di HMPA e Ni (II) sali nella reazione Samario Barbier

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of ...

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Preparation and Use of Samarium Diiodide (SmI2) in Organic Synthesis: The Mechanistic Role of HMPA and Ni(II) Salts in the Samarium Barbier Reaction

32.8K Views.  Lehigh University. Una procedura semplice per la preparazione di samario diioduro (SMI 2) In THF viene descritto. Il ruolo dei due principali additivi cioè esametilfosforammide (HMPA) e Ni (acac) 2 In Sm reazioni mediate è dimostrato nella Sm-Barbier reazione.

Video: Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction

Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid phase by using combinatorial chemistry. One of the most well studied classes of peptidomimetics is peptoids. Peptoids are easy to synthesize and have been shown to be proteolysis-resistant and cell-permeable. Over the past decade, many useful protein ligands have been identified through screening of peptoid libraries. However, most of the ligands identified from peptoid libraries do not display high affinity, with rare exceptions. This may be due, in part, to the lack of chiral centers and conformational constraints in peptoid molecules. Recently, we described a new synthetic route to access peptide tertiary amides (PTAs). PTAs are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. With side chains on both &#945;-carbon and main chain nitrogen atoms, the conformation of these molecules are greatly constrained by sterical hindrance and allylic 1,3 strain. (Figure 1) Our study suggests that these PTA molecules are highly structured in solution and can be used to identify protein ligands. We believe that these molecules can be a future source of high-affinity protein ligands. Here we describe the synthetic method combining the power of both split-and-pool and sub-monomer strategies to synthesize a sample one-bead one-compound (OBOC) library of PTAs.

Peptide tertiary amides (PTAs) are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. Here we describe a synthetic method which combines&#160;both split-and-pool and sub-monomer strategies to synthesize a one-bead one-compound library of PTAs.

Split-e-pool Sintesi e caratterizzazione di peptidi Terziario Ammide Biblioteca

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid ...

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Chimica

Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. Isonicotinic acid, or its derivatives, are coupled to variable length diaminoalkane chains under an inert atmosphere in anhydrous DMF or DMSO with the use of a weak base, triethylamine, and a coupling agent, 1-propylphosphonic anhydride. The products precipitate from solution upon formation or can be precipitated by the addition of water. If desired, the ligands can be further purified by recrystallization from hot water. Dinuclear platinum complex synthesis using the bispyridine ligands is done in hot water using transplatin. The most informative of the chemical characterization techniques to determine the structure and gross purity of both the bispyridine ligands and the final platinum complexes is 1H NMR with particular analysis of the aromatic region of the spectra (7-9 ppm). The platinum complexes have potential application as anticancer agents and the synthesis method can be modified to produce trinuclear and other multinuclear complexes with different hydrogen bonding functionality in the bridging ligand.

This protocol describes the use of amide coupling reactions of isonicotinic acid and diaminoalkanes to form bridging ligands suitable for use in the synthesis of multinuclear platinum complexes, which combine aspects of the anticancer drugs BBR3464 and picoplatin.

Ammide Accoppiamento di reazione per la sintesi di leganti a base di Bispyridine e il loro Complessazione di platino come diciclici agenti antitumorali

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. ...

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Sintesi e caratterizzazione di funzionalizzato metallo-organici quadri

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

Preparation and Use of Carbonyl-decorated Carbenes in the Activation of White Phosphorus

Here we present a protocol for the synthesis of two distinct carbonyl-decorated carbenes. Both carbenes can be prepared using nearly identical procedures in multi-gram scale quantities. The goal of this manuscript is to clearly detail how to handle and prepare these unique carbenes such that a synthetic chemist of any skill level can work with them. The two carbenes described are a diamidocarbene (DAC, carbene 1) and a monoamidoaminocarbene (MAAC 2). These carbenes are highly electron-deficient and as such display reactivity profiles that are atypical of more traditional N-heterocyclic carbenes. Additionally, these two carbenes only differ in their electrophilic character and not their steric parameters, making them ideal for studying how carbene electronics influence reactivity. To demonstrate this phenomenon, we are also describing the activation of white phosphorus (P4) using these carbenes. Depending on the carbene used, two very different phosphorus-containing compounds can be isolated. When the DAC 1 is used, a tris(phosphaalkenyl)phosphane can be isolated as the exclusive product. Remarkably however, when MAAC 2 is added to P4 under identical reaction conditions, an unexpected carbene-supported P8&#160;allotrope of phosphorus is isolated exclusively. Mechanistic studies demonstrate that this carbene-supported P8allotrope forms via a [2+2] cycloaddition dimerization of a transient diphosphene which has been trapped by treatment with 2,3-dimethyl-1,3-butadiene.

Here, we present a protocol for the synthesis of two carbonyl-decorated carbenes. The protocol makes these interesting compounds readily available to chemists of all skill levels. In addition to the synthesis of these two carbenes, their use in the activation of white phosphorus is also described.

Preparazione e utilizzo di carbeni carbonile-decorate in Attivazione di fosforo bianco

Here we present a protocol for the synthesis of two distinct carbonyl-decorated carbenes. Both carbenes can be prepared using nearly identical procedures ...

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional groups and scaffolds. Traditional methods for the preparation of ynones are associated with drawbacks including harsh conditions, multiple purification steps, and the presence of unwanted byproducts. An alternative method for the straightforward preparation of ynones from acyl chlorides and potassium alkynyltrifluoroborate salts is described herein. The adoption of organotrifluoroborate salts as an alternative to organometallic reagents for the formation of new carbon-carbon bonds has a number of advantages. Potassium organotrifluoroborate salts are shelf stable, have good functional group tolerance, low toxicity, and a wide variety are straightforward to prepare. The title reaction proceeds rapidly at ambient temperature in the presence of a Lewis acid without the exclusion of air and moisture. Fair to excellent yields may be obtained via reaction of various aryl and alkyl acid chlorides with alkynyltrifluoroborate salts in the presence of boron trichloride.

The goal of this manuscript is to demonstrate a straightforward method for the preparation of ynones from acyl chloride and potassium alkynyltrifluoroborate salt starting materials. The one-pot reaction proceeds rapidly in the presence of boron trichloride without exclusion of air and moisture.

Sintesi senza metallo di Ynones da Acyl Cloruri e Potassio Alkynyltrifluoroborate Sali

Ynones are a valuable functional group and building block in organic synthesis. Ynones serve as a precursor to many important organic functional groups ...

Synthesis and Reaction Chemistry of Nanosize Monosodium Titanate

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the material with Au(III) ions. The synthesis method was derived from a sol-gel process used to produce micron-sized monosodium titanate (MST), with several key modifications, including altering reagent concentrations, omitting a particle seed step, and introducing a non-ionic surfactant to facilitate control of particle formation and growth. The resultant nMST material exhibits spherical-shaped particle morphology with a monodisperse distribution of particle diameters in the range from 100 to 150&#160;nm. The nMST material was found to have a Brunauer-Emmett-Teller (BET) surface area of 285 m2g-1, which is more than an order of magnitude higher than the micron-sized MST. The isoelectric point of the nMST measured 3.34 pH units, which is a pH unit lower than that measured for the micron-size MST. The nMST material was found to serve as an effective ion exchanger under weakly acidic conditions for the preparation of an Au(III)-exchange nanotitanate. In addition, the formation of the corresponding peroxotitanate was demonstrated by reaction of the nMST with hydrogen peroxide.

The surfactant mediated sol-gel synthesis of nanosized monosodium titanate is described, along with preparation of the corresponding peroxide modified material. An ion-exchange reaction with Au(III) is also presented.

Sintesi e Reazione chimica della nanosize monosodico titanato

This paper describes the synthesis and peroxide-modification of nanosize monosodium titanate (nMST), along with an ion-exchange reaction to load the ...

Synthesis and Characterization of Supramolecular Colloids

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

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

Sintesi e caratterizzazione di supramolecolari colloidi

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

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the development of antibody drug conjugates (ADCs) and nanomedicine, fluorescent microscopy and systems chemistry. For many of these applications, specificity of the bioconjugation method used is of prime concern. The Michael addition of maleimides with cysteine(s) on the target proteins is highly selective and proceeds rapidly under mild conditions, making it one of the most popular methods for protein bioconjugation.
We demonstrate here the modification of the only surface-accessible cysteine residue on yeast cytochrome c with a ruthenium(II) bisterpyridine maleimide. The protein bioconjugation is verified by gel electrophoresis and purified by aqueous-based fast protein liquid chromatography in 27% yield of isolated protein material. Structural characterization with MALDI-TOF MS and UV-Vis is then used to verify that the bioconjugation is successful. The protocol shown here is easily applicable to other cysteine - maleimide coupling of proteins to other proteins, dyes, drugs or polymers.

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

This protocol details the important steps required for the bioconjugation of a cysteine containing protein to a maleimide, including reagent purification, reaction conditions, bioconjugate purification and bioconjugate characterization.

Sintesi di proteine ​​bioconiugati<em&gt; via</em&gt; Chimica cisteina-maleimmide

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the ...

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single molecule level. An electrostatic self-assembly and covalent fixation (ESA-CF) process is used for the synthesis of the cyclic poly(tetrahydrofuran) (poly(THF)). The diffusive motion of individual cyclic polymer chains in a melt state is visualized using single molecule fluorescence imaging by incorporating a fluorophore unit in the cyclic chains. The diffusive motion of the chains is quantitatively characterized by means of a combination of mean-squared displacement (MSD) analysis and a cumulative distribution function (CDF) analysis. The cyclic polymer exhibits multiple-mode diffusion which is distinct from its linear counterpart. The results demonstrate that the diffusional heterogeneity of polymers that is often hidden behind ensemble averaging can be revealed by the efficient synthesis of the cyclic polymers using the ESA-CF process and the quantitative analysis of the diffusive motion at the single molecule level using the MSD and CDF analyses.

A protocol for the synthesis and characterization of diffusive motion of cyclic polymers at the single molecule level is presented.

Sintesi di ciclici polimeri e caratterizzazione di loro moto diffusivo allo stato fuso alla molecola Piano unico

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single ...

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 benzimidazolium salts. Detailed and generalized protocols are also presented for testing the catalytic activity of such complexes in arylation and Suzuki-Miyaura cross-coupling reactions. Representative results are shown for the catalytic activity of the four complexes in arylation and Suzuki-Miyaura type reactions. For each of the reactions investigated, at least one of the four complexes successfully catalyzed the reaction, qualifying them as promising candidates for catalysis of many carbon-carbon bond-forming reactions. The protocols presented are general enough to be adapted for the synthesis, purification and catalytic activity testing of new palladium N-heterocyclic carbene complexes.

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 benzimidazolium salts. The complexes were tested for catalytic activity in arylation and Suzuki-Miyaura reactions. For each reaction investigated, at least one of the four complexes successfully catalyzed the reaction.

Palladio<em&gt; N</em&gt; Complessi di Carbene eterocicliche: Sintesi dei sali di benzimidazolium e attività catalitica in reazioni di formazione di legame di carbonio-carbonio

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