The authors would like to acknowledge the University of Colorado Boulder for its support of this work.

ACHTUNG: Viele der in diesem Protokoll verwendeten Chemikalien sind gefährliche Substanzen. Consult Sicherheitsdatenblätter (MSDS) und geeignete persönliche Schutzausrüstung (PSA) verwenden, wenn sie mit diesen Stoffen arbeiten. 1. Reinigung, Vorbereitung und Lagerung der Reagenzien <ol><li> Reinige alle Lösungsmittel werden verwendet, um ein Lösungsmittelreinigungssystem unter Verwendung von nach dem Protokoll des Herstellers. Wenn ein Lösungsmittelreinigungssystem nicht verfügbar ist, verwenden Trocknungsmittel (beispielsweise Molekularsiebe, CaH 2, etc.) und Destillation. Einmal getrocknet, speichern Lösungsmittel unter Stickstoffatmosphäre in der Glovebox bei Raumtemperatur. </li><li> Reinige alle Monomere durch Vakuumdestillation nach dem Protokoll des Herstellers. Einmal destilliert, speichern Monomere in dunklen Flaschen unter einer Stickstoffatmosphäre in einem Kühlschrank. </li><li> Reinige Initiatoren durch Vakuumdestillation nach dem Protokoll des Herstellers. Einmal destilliert, speichern Initiatoren indunklen Flaschen unter einer Stickstoffatmosphäre in einem Kühlschrank. </li><li> Man reinige das Perylen durch Sublimation nach dem Protokoll des Herstellers. Sobald sublimiert, speichern Sie die Perylen am Prüfplatz bei Raumtemperatur. </li><li> Bereiten Sie eine 250 ppm Lösung von butyliertem Hydroxytoluol (BHT) in deuteriertem Chloroform (CDCl 3) durch Zugabe von 25,0 mg BHT zu 100 g Flasche CDCl 3. Bereiten Sie und speichern diese Lösung am Prüfplatz. </li></ol> 2. Photopolymerisation von Methylmethacrylat unter Verwendung von Perylen als der Photokatalysator <ol><li> Alle Reagenzien auf Raumtemperatur kommen. Überprüfen Sie alle Reagenzien vor dem Gebrauch, um sicherzustellen, keine Anzeichen einer Kontamination ist, wie Verfärbung oder Bildung von festen Partikeln. </li><li> In einer Stickstoffatmosphäre Glovebox, legen Sie eine kleine Rührstab in einem 20 ml Szintillationsphiole. Hinzufügen 2,36 mg (9,38 &amp; mgr; mol, 1,00 Äquiv.) Von Perylen. </li><li> In 1,00 ml Dimethylformamid (DMF). </li><li> Zu dieser Mischung hinzufügen 1,00 ml (9,38 mmol,1,000 eq.) Methylmethacrylat (MMA). </li><li> Legen Sie das Fläschchen auf einer Rührplatte auf 1600 Umdrehungen pro Minute und beleuchtet durch Streifen aus weißen Leuchtdioden (LEDs). Begrenzen Sie jede Beleuchtung von anderen Lichtquellen (zB Deckenbeleuchtung, in der Nähe Fenster). </li><li> Um die Reaktion zu initiieren, fügen 16,4 ul (93,8 &amp; mgr; mol, 10,0 Äq.) Von α-Ethyl Bromphenyl Acetat (EBP) über eine Pipette. Hinweis: Um diese Reaktion durchführen mit natürlichem Sonnenlicht, die oben beschriebenen Schritte, ohne auf Schritt 2.5, dann verschließen Sie das Fläschchen, bringen sie aus dem Handschuhfach, und legen Sie das Fläschchen in einem Bereich von natürlichem Sonnenlicht beleuchtet. </li><li> Rühre das Reaktionsgemisch 24 h unter konstanter Beleuchtung. Isolieren und das Produkt Poly (MMA) reinigen, indem Sie die Anweisungen in den Schritten von 4,1 bis 4,4. </li></ol> 3. Kinetische Analyse der Reaktions <ol><li> Auf Prüfplatz, verzichtet werden 0,70 ml der BHT in CDCl 3 -Lösung in ein 2 ml - Fläschchen und Dichtung mit Septumdeckel. Bringen Sie diese Fläschchen i<html> nde glovebox wobei die Polymerisation durchgeführt wird. </li><li> Mit einer Spritze 0,20 ml der Reaktionsmischung zu entfernen. Injizieren Sie den Inhalt der Spritze in die 2 ml Fläschchen , die 250 - ppm - Lösung von BHT in CDCl , die 3. Zeichnen Sie zurück und schieben in den Kolben mehrmals gründlich Abschrecken der Polymerisation zu gewährleisten. </li><li> Übertragen, um den Inhalt des 2 ml Phiole auf eine NMR (magnetische Kernresonanz) -Spektroskopie Röhre. Analysieren Sie diese Probe über 1 H - NMR - Spektroskopie für die prozentuale Umwandlung. 24 </li><li> Für das spezielle Beispiel der Polymerisation von Methylmethacrylat Perylen verwendet, die prozentuale Umwandlung von dem 1 H NMR - Spektrum der Probe zu berechnen , indem die Fläche unter dem Peak Vergleich zu den methoxy - Wasserstoffatome des nicht umgesetzten Monomers entspricht , (δ = 3,62) (M) und das Fläche unter dem Peak der methoxy-Wasserstoffatome des Polymers (δ = 3,50) (P) mit der folgenden Formel entsprechen: 1 &quot;src =&quot; / files / ftp_upload / 53571 / 53571eq1.jpg &quot;/&gt; </li><li> Nach der Analyse schütten den Inhalt der NMR-Spektroskopie Rohr in einen sauberen 20 ml-Szintillations-Phiole. Dampfe das Lösungsmittel unter vermindertem Druck. Wieder aufzulösen die Probe in 1,00 ml Tetrahydrofuran (THF). </li><li> Senden Sie die Probe durch einen Spritzenfilter in ein sauberes 2 ml Fläschchen. Analysieren der Probe mittels Gelpermeationschromatographie (GPC) in Verbindung mit Mehrfachwinkel - Lichtstreuungszahlenmittleren Molekulargewicht (M n), gewichtsgemittelte Molekulargewicht (M w) zu bestimmen, und die Dispersität (dj). 24 </li></ol> 4. Isolierung und Reinigung des Produktpolymers <ol><li> Quenche die Polymerisationsreaktion durch die Inhalte des Reaktionsgemisches in einem 50-fachen Überschuß an Methanol gegossen und ließ rühren für mindestens 1 Std. </li><li> Isolieren des Poly (methylmethacrylat) aus dem Methanol durch Vakuumfiltration nach HerstellerProtokoll. Hinweis: Die Isolationsmethode variiert in Abhängigkeit von dem erzeugten Polymer. Für Poly (methylmethacrylat) und Polystyrol, Vakuum, um das ausgefallene Polymer von dem Methanol Filter einen Büchner-Trichter verwendet wird. Für Poly (butylacrylat), dekantiert die Methanol aus dem viskosen Polymer. </li><li> Spülen Sie das Polymer mit einem Methanol ml zusätzlich 100. </li><li> Re-Auflösung des Polymers in Dichlormethan und wiederholen Sie die Schritte 4.1 bis 4.3 oben zweimal. </li></ol> 5. Kettenverlängerung des MMA Makroinitiator mit Styrol zu produzieren Poly (MMA) -b-poly (S) <ol><li> Alle Reagenzien auf Raumtemperatur kommen. Überprüfen Sie alle Reagenzien vor dem Gebrauch, um sicherzustellen, keine Anzeichen einer Kontamination ist, wie Verfärbung oder Bildung von festen Partikeln. </li><li> In einer Stickstoffatmosphäre Glovebox legen 136 mg (2,34 &amp; mgr; mol, 1,00 Äq.) Von Poly (MMA) Makroinitiator in ein 20 ml Szintillationsphiole mit einem kleinen Rührstab. </li><li> In 0,59 mg Perylen (2,34 &amp; mgr; mol, 1,00 eq.). </li><li> In 1,00 ml DMF. </li><li> Legen Sie das Fläschchen auf einer Rührplatte auf 1600 Umdrehungen pro Minute und beleuchtet von Streifen aus weißen LEDs. Begrenzen Sie jede Beleuchtung von anderen Lichtquellen (zB Deckenbeleuchtung, in der Nähe Fenster). </li><li> Zu dieser Mischung, fügen 1,24 ml (11,7 mmol, 5,000 eq.) Styrol (S) über eine Pipette. </li><li> Rühre das Reaktionsgemisch 24 h unter konstanter Beleuchtung. Isolieren und zu reinigen das Produkt Poly (MMA) -b-poly (S) gemäß den Anweisungen in den Schritten von 4,1 bis 4,4. </li></ol>

<ol>
	<li>Bates, F. S., Hillmyer, M. A., Lodge, T. P., Bates, C. M., Delaney, K. T., Fredrickson, G. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiblock+Polymers:+Panacea+or+Pandora's+Box.">Multiblock Polymers: Panacea or Pandora's Box.</a> Science. 336 (6080), 434-440 (2012).</li><li>Hawker, C. J., Wooley, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Convergence+of+Synthetic+Organic+and+Polymer+Chemistries.">The Convergence of Synthetic Organic and Polymer Chemistries.</a> Science. 309 (5738), 1200-1205 (2005).</li><li>di Lena, F., Matyjaszewski, K. <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+Catalysts+for+Controlled+Radical+Polymerization.">Transition Metal Catalysts for Controlled Radical Polymerization.</a> Prog. Polym. Sci. 35 (8), 959-1021 (2010).</li><li>Rosen, B. M., Percec, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-Electron+Transfer+and+Single-Electron+Transfer+Degenerative+Chain+Transfer+Living+Radical+Polymerization.">Single-Electron Transfer and Single-Electron Transfer Degenerative Chain Transfer Living Radical Polymerization.</a> Chem. Rev. 109 (11), 5069-5119 (2009).</li><li>Moad, G., Rizzardo, E., Thang, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toward+Living+Radical+Polymerization.">Toward Living Radical Polymerization.</a> Acc. Chem. Res. 41 (9), 1133-1142 (2008).</li><li>Braunecker, W. A., Matyjaszewski, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlled/living+Radical+Polymerization:+Features,+Developments,+and+Perspectives.">Controlled/living Radical Polymerization: Features, Developments, and Perspectives.</a> Prog. Polym. Sci. 32 (1), 93-146 (2007).</li><li>Kamigaito, M., Ando, T., Sawamoto, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal-Catalyzed+Living+Radical+Polymerization.">Metal-Catalyzed Living Radical Polymerization.</a> Chem. Rev. 101 (12), 3689-3746 (2001).</li><li>Matyjaszewski, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+and+Classifications+of+Controlled/Living+Radical+Polymerizations.">Comparison and Classifications of Controlled/Living Radical Polymerizations.</a> ACS Symp. Ser. 768 (1), 2-26 (2000).</li><li>Matyjaszewski, K., Tsarevsky, N. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macromolecular+Engineering+by+Atom+Transfer+Radical+Polymerization.">Macromolecular Engineering by Atom Transfer Radical Polymerization.</a> J. Am. Chem. Soc. 136 (18), 6513-6533 (2013).</li><li>Matyjaszewski, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atom+Transfer+Radical+Polymerization+(ATRP):+Current+Status+and+Future+Perspectives.">Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives.</a> Macromolecules. 45 (10), 4015-4039 (2012).</li><li>Ouchi, M., Terashima, T., Sawamoto, M. <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+Living+Radical+Polymerization:+Toward+Perfection+in+Catalysis+and+Precision+Polymer+Synthesis.">Transition Metal-Catalyzed Living Radical Polymerization: Toward Perfection in Catalysis and Precision Polymer Synthesis.</a> Chem. Rev. 109 (11), 4963-5050 (2009).</li><li>Matyjaszewski, K., Tsarevsky, N. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanostructured+Functional+Materials+Prepared+by+Atom+Transfer+Radical+Polymerization.">Nanostructured Functional Materials Prepared by Atom Transfer Radical Polymerization.</a> Nat. Chem. 1 (4), 276-288 (2009).</li><li>Ouchi, M., Terashima, T., Sawamoto, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precision+Control+of+Radical+Polymerization+via+Transition+Metal+Catalysis:+From+Dormant+Species+to+Designed+Catalysts+for+Precision+Functional+Polymers.">Precision Control of Radical Polymerization via Transition Metal Catalysis: From Dormant Species to Designed Catalysts for Precision Functional Polymers.</a> Acc. Chem. Res. 41 (9), 1120-1132 (2008).</li><li>Matyjaszewski, K., Xia, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atom+Transfer+Radical+Polymerization.">Atom Transfer Radical Polymerization.</a> Chem. Rev. 101 (9), 2921-2990 (2001).</li><li>Magenau, A. J. D., Strandwitz, N. C., Gennaro, A., Matyjaszewski, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrochemically+Mediated+Atom+Transfer+Radical+Polymerization.">Electrochemically Mediated Atom Transfer Radical Polymerization.</a> Science. 332 (6025), 81-84 (2011).</li><li>Matyjaszewski, K., 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=Diminishing+Catalyst+Concentration+in+Atom+Transfer+Radical+Polymerization+with+Reducing+Agents.">Diminishing Catalyst Concentration in Atom Transfer Radical Polymerization with Reducing Agents.</a> Proc. Natl. Acad. Sci. U.S.A. 103 (42), 15309-15314 (2006).</li><li>Moad, G., Rizzardo, E., Thang, S. 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+Radical+Polymerization+by+the+RAFT+Process-+A+Second+Update.">Living Radical Polymerization by the RAFT Process- A Second Update.</a> Aust. J. Chem. 62 (11), 1402-1472 (2009).</li><li>Moad, G., Rizzardo, E., Thang, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radical+Addition-Fragmentation+Chemistry+in+Polymer+Synthesis.">Radical Addition-Fragmentation Chemistry in Polymer Synthesis.</a> Polymer. 49 (5), 1079-1131 (2008).</li><li>Nicolas, 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=Nitroxide-Mediated+Polymerization.">Nitroxide-Mediated Polymerization.</a> Prog. Polym. Sci. 38 (1), 63-235 (2013).</li><li>Hawker, C. J., Bosman, A. W., Harth, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+Polymer+Synthesis+by+Nitroxide+Mediated+Living+Radical+Polymerizations.">New Polymer Synthesis by Nitroxide Mediated Living Radical Polymerizations.</a> Chem. Rev. 101 (12), 3661-3688 (2001).</li><li>Goto, A., Wakada, T., Fukuda, T., Tsujii, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Systematic+Kinetic+Study+in+Reversible+Chain+Transfer+Catalyzed+Polymerizations+(RTCPs)+with+Germanium,+Tin,+Phosphorus,+and+Nitrogen+Catalysts.">A Systematic Kinetic Study in Reversible Chain Transfer Catalyzed Polymerizations (RTCPs) with Germanium, Tin, Phosphorus, and Nitrogen Catalysts.</a> Macromol. Chem. Phys. 211 (5), 594-600 (2010).</li><li>Goto, A., Ohtsuki, A., Ohfuji, H., Tanishima, M., Kaji, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversible+Generation+of+a+Carbon-Centered+Radical+from+Alkyl+Iodide+Using+Organic+Salts+and+Their+Application+as+Organic+Catalysts+in+Living+Radical+Polymerization.">Reversible Generation of a Carbon-Centered Radical from Alkyl Iodide Using Organic Salts and Their Application as Organic Catalysts in Living Radical Polymerization.</a> J. Am. Chem. Soc. 135 (30), 11131-11139 (2013).</li><li>Goto, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversible+Complexation+Mediated+Living+Radical+Polymerization+(RCMP)+Using+Organic+Catalysts.">Reversible Complexation Mediated Living Radical Polymerization (RCMP) Using Organic Catalysts.</a> Macromolecules. 44 (22), 8709-8715 (2011).</li><li>Miyake, G. M., Theriot, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perylene+as+an+Organic+Photocatalyst+for+the+Radical+Polymerization+of+Functionalized+Vinyl+Monomers+Through+Oxidative+Quenching+With+Alkyl+Bromides+and+Visible+Light.">Perylene as an Organic Photocatalyst for the Radical Polymerization of Functionalized Vinyl Monomers Through Oxidative Quenching With Alkyl Bromides and Visible Light.</a> Macromolecules. 47 (23), 8255-8261 (2014).</li><li>Miyake, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organocatalyzed+Photoredox+Mediated+Polymerization+Using+Visible+Light.">Organocatalyzed Photoredox Mediated Polymerization Using Visible Light.</a> US Patent Application. 14, (2013).</li><li>Treat, N. 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=Metal-Free+Atom+Transfer+Radical+Polymerization.">Metal-Free Atom Transfer Radical Polymerization.</a> J. Am. Chem. Soc. 136 (45), 16096-16101 (2014).</li><li>Pan, X., Lamson, M., Yan, J., Matyjaszewski, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoinduced+Metal-Free+Atom+Transfer+Radical+Polymerization+of+Acrylonitrile.">Photoinduced Metal-Free Atom Transfer Radical Polymerization of Acrylonitrile.</a> ACS Macro Lett. 4 (2), 192-196 (2015).</li></ol>

The authors have nothing to disclose.

Obwohl das Protokoll ein spezielles Beispiel dieser Polymerisationstechnik zeigt, sind die Optionen zur Verfügung, die Forscher diese Reaktion durchführen ziemlich breit. Modifikationen können überall in das Protokoll an einer Anzahl von Punkten vorgenommen werden, um die Optimierung zu ermöglichen, wie auch immer bestimmten Photoredox- ATRP durchgeführt wird. Als neue Monomere, Initiatoren und Katalysatoren für diese Reaktion unter Untersuchung kommen, die Stöchiometrie und Lösungsmittel verwendet, um die Reaktion durchführen kann und soll im Rahmen der Optimierung der Reaktionsbedingungen modifiziert werden. Zusätzlich können einzelne Experimentatoren wählen Tabelle 1 als Richtlinie zu verwenden , um andere Parameter zu ändern, wie Reaktions Konzentration, Lichtquelle (ob LED oder natürliches Sonnenlicht) und Temperatur, um die Reaktion auf die genauen Ergebnisse stimmen gewünscht. Die Grenzen dieser Methode sind ähnlich zu anderen, verwandten Polymerisationen. Die Reaktion ist empfindlich gegen oxygen, so rigorosen Reinigung jeder Reaktionskomponente erforderlich ist. Wenn die Ergebnisse dieses Verfahrens sind nicht als konsistent gefunden, Verunreinigung der Reagenzien ist die wahrscheinlichste suspekt. Achten Sie immer darauf, dass alle Reagenzien gereinigt, aufbereitet und gespeichert als 1. Zusätzlich in Teil, in Teil der Reinigungsprozess 3 kann modifiziert werden müssen, wenn unterschiedliche Synthese von Polymeren nach dem Löslichkeitsprofils des jeweiligen Polymers. Schließlich ist es wichtig zu beachten, dass herkömmliche, unkontrollierter radikalischer Polymerisation auftreten kann, wenn der Lichtstrom oder der Temperatur zu hoch ist. Dieses Problem kann durch eine bimodale Molekulargewichtsverteilung und / oder hohe Werte von Đ (&gt; 2.0) angegeben werden. Es wird empfohlen, einen Lüfter zu verwenden, um die Temperatur in der Glovebox als nahe der Raumtemperatur wie möglich zu halten. Wenn der Lichtfluss vermutet wird, zu hoch zu sein, ist es empfehlenswert, entweder die Anzahl der LEDs zu reduzieren verwendet oder der Spannung an die LEDs geliefert zu reduzieren. ZusätzlichExperimente sind derzeit im Gange, die optimale Lichtstrom Bereich genau zu bestimmen, die Kontrolle über die Polymerisation zu gewährleisten. Die Ergebnisse zeigen , dass Perylen Lage ist , über eine oxidative Abschreckungs Stoffwechselweg radikalische Polymerisation einer Reihe von funktionalisierten Vinylmonomeren vermitteln. Kontrollexperimente, bei denen entweder der Katalysator, Initiator oder Lichtquelle zurückgehalten wurde, zeigte, dass alle drei dieser Komponenten erforderlich sind, um die Polymerisation fortzusetzen. Zusätzliche Kontrollversuche zeigen auch, dass die Verwendung von Luft-Ausschlussverfahren (in diesem Fall einer Glovebox) notwendig ist, da die Anwesenheit von Sauerstoff nicht Polymerisation auftreten lassen. Ein gepulster Licht Sequenz zeigte, dass die Polymerisation gestoppt und wieder aufgenommen werden kann, indem die Lichtquelle ausgeschaltet und wieder eingeschaltet wird, so dass für die zeitliche Kontrolle über die Reaktion. Unterstützung für ein Atom-Transfer-Mechanismus umkehrbar-Deaktivierung erfolgt durch Kettenverlängerung Experimente, wie sie in gefunden &lt;strong&gt; 1. Wenn sie mit den relativ niedrigen Đ Werte gekoppelt ist, die in Tabelle 1 gefunden werden können, gibt es Hinweise darauf , dass diese Polymerisation ein Beispiel Photoredox- ist ATRP organokatalysierten, seiner Art unter den ersten. Da diese neue Art von ATRP zu entwickeln und zu erweitern weiter, wird es eine Notwendigkeit, zu entwerfen, zu testen und viele neue potentielle Katalysatoren für die Reaktion zu optimieren. Eine solche wird die zukünftige Arbeit am einfachsten, es zu interpretieren, wenn die Konsistenz und Transparenz in den Verfahren verwendet wird, ist diese Reaktionen zu untersuchen. Hier haben wir die Methode mitgeteilt, durch die wir verwenden und zu bewerten Organokatalysatoren für sichtbares Licht vermittelte Atomübertragungsradikalpolymerisation.

The synthesis of technologically advanced polymers requires precise control over polymer molecular weight, dispersity (&#208;), composition, and architecture.1,2 Controlled radical polymerizations (CRPs)3-8 have revolutionized the synthesis of well-defined polymers, with atom transfer radical polymerization (ATRP) being the most used CRP, largely due to operational simplicity and synthetic versatility.9-14 The crux of ATRP is the ability to reversibly deactivate the polymerization, controlling the equilibrium between a propagating radical and a dormant species. Enforcing a low concentration of active radicals greatly minimizes bimolecular termination pathways and allows for the synthesis of well-defined polymers. 
Traditional ATRP relies on a transition metal catalyst to mediate this equilibrium.3 These metal catalysts contaminate the polymer product and impede implementation in biomedical or electronic applications while also raising environmental concerns. Although significant strides have been made to reduce the catalyst concentration to ppm levels, these methodologies require more demanding experimental conditions and metal contamination is still not entirely eliminated.15,16
Reversible addition-fragmentation transfer17,18 and nitroxide-mediated polymerizations19,20 are CRPs that do not require metal catalysts, although they have been used less often than ATRP.3 Recently, reversible chain-transfer21 and reversible complexation22,23 variants of ATRP that can use organic catalysts were reported. However, these methodologies require the use of alkyl iodide initiators and are not effective with the alkyl bromides commonly employed in ATRP. A highly desirable CRP would match the performance, feasibility, and robustness of traditional ATRP while being catalyzed by an organic catalyst under mild conditions.
Here, we describe a methodology for the radical polymerization of functionalized vinyl monomers using perylene as a visible-light photocatalyst. Through optimization of parameters such as stoichiometry, concentration, time, and light flux, the molecular weight of the polymers can be controlled.24, 25 Similar methodologies have been recently introduced using phenothiazine derivatives as photocatalysts for metal-free ATRP.26, 27 Because researchers in the field of polymerization catalysis are constantly developing new catalytic systems, the ability to compare catalyst performance across a number of metrics is vital. This ability to make comparisons relies heavily upon procedural consistency and clarity on the part of the researchers performing the experiments. As such, it is our goal that this video will be used to help precisely communicate the methods by which these polymers are synthesized and characterized.

<table border="0" cellpadding="0" cellspacing="0" width="572">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">perylene, min 98.0%</td>
			<td style="width:92px;">TCI America</td>
			<td style="width:128px;">TCP0078-025G</td>
			<td style="width:147px;">purify by sublimation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">N,N-dimethylformamide</td>
			<td style="width:92px;">VWR</td>
			<td style="width:128px;">EM-DX1726-1</td>
			<td style="width:147px;">Omnisolv</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:205px;">methyl methacrylate, 99%</td>
			<td style="width:92px;">VWR</td>
			<td style="width:128px;">200000-678</td>
			<td style="width:147px;">distilled prior to use, stored in refrigerator</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">ethyl &#945;-bromophenyl acetate&#160;</td>
			<td style="width:92px;">Aldrich</td>
			<td style="width:128px;">554065</td>
			<td style="width:147px;">distilled prior to use stored in refrigerator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">butylated hydroxytoluene&#160;</td>
			<td style="width:92px;">Aldrich</td>
			<td style="width:128px;">W218405</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Chloroform-D</td>
			<td style="width:92px;">Cambridge Isotope Labs</td>
			<td style="width:128px;">DLM-7-100</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">tetrahydrofuran</td>
			<td style="width:92px;">VWR</td>
			<td style="width:128px;">EM-TX0279-1</td>
			<td style="width:147px;">Omnisolv</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">methanol</td>
			<td style="width:92px;">VWR</td>
			<td style="width:128px;">BDH1135</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">dichloromethane</td>
			<td style="width:92px;">VWR</td>
			<td style="width:128px;">EM-DX0831-1</td>
			<td style="width:147px;">Omnisolv</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:205px;">styrene, 99%</td>
			<td style="width:92px;">VWR</td>
			<td style="width:128px;">AAAA18481-0F</td>
			<td style="width:147px;">distilled prior to use, stored in refrigerator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">glass scintillation vial, 20 mL</td>
			<td style="width:92px;">VWR</td>
			<td style="width:128px;">66022-065</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">screw top vial, 2 mL</td>
			<td style="width:92px;">Agilent</td>
			<td style="width:128px;">5182-0715</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">septum cap for screw top vial</td>
			<td style="width:92px;">Agilent</td>
			<td style="width:128px;">5182-0717</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:205px;">heavy wall pressure vessel, 100 mL</td>
			<td style="width:92px;">Synthware</td>
			<td style="width:128px;">P160005&#160;</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">syringe, 1 mL norm-ject</td>
			<td style="width:92px;">VWR</td>
			<td style="width:128px;">89174-491</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">NMR tube</td>
			<td style="width:92px;">New Era</td>
			<td style="width:128px;">NE-UL5-7&#39;</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">nylon syringe filter, 0.45 um</td>
			<td style="width:92px;">VWR</td>
			<td style="width:128px;">28143-240</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">glovebox</td>
			<td style="width:92px;">Mbraun</td>
			<td style="width:128px;">LABstar</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">solvent purification system</td>
			<td style="width:92px;">Mbraun</td>
			<td style="width:128px;">MB-SPS-800</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">stirplate</td>
			<td style="width:92px;">IKA</td>
			<td style="width:128px;">3582401</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:205px;">light-emitting diodes</td>
			<td style="width:92px;">Creative Lighting Solutions</td>
			<td style="width:128px;">CL-FRS1210-5M-12V-WH</td>
			<td style="width:147px;">2x 12-inch strips of 5500 K white LEDs were used for illumination</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:205px;">12V DC power supply for LEDs</td>
			<td style="width:92px;">Creative Lighting Solutions</td>
			<td style="width:128px;">CL-PS16001-40W</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:205px;">high performance liquid chromatograph&#160;</td>
			<td style="width:92px;">Agilent</td>
			<td style="width:128px;">G1310B, G1322A, G1329B, G1316A</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:205px;">gel permeation size-exclusion columns</td>
			<td style="width:92px;">Agilent</td>
			<td style="width:128px;">PL1110-6500</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:205px;">multi-angle light scattering detector</td>
			<td style="width:92px;">Wyatt</td>
			<td style="width:128px;">WTREOS</td>
			<td style="width:147px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:205px;">differential refractometer</td>
			<td style="width:92px;">Wyatt</td>
			<td style="width:128px;">WTREX</td>
			<td style="width:147px;"></td>
		</tr>
	</tbody>
</table>

atom transfer radical polymerization of functionalized vinyl monomers using perylene as a visible light photocatalyst

A standardized technique for atom transfer radical polymerization of vinyl monomers using perylene as a visible-light photocatalyst is presented. The procedure is performed under an inert atmosphere using air- and water-exclusion techniques. The outcome of the polymerization is affected by the ratios of monomer, initiator, and catalyst used as well as the reaction concentration, solvent, and nature of the light source. Temporal control over the polymerization can be exercised by turning the visible light source off and on. Low dispersities of the resultant polymers as well as the ability to chain-extend to form block copolymers suggest control over the polymerization, while chain end-group analysis provides evidence supporting an atom-transfer radical polymerization mechanism.

Tabelle 1 zeigt den Bereich der Polymerisationsergebnisse erreichbar durch diese Methode. Diese Daten zeigen, dass Perylen ist in der Lage für die Polymerisation von einer Anzahl von funktionalisierten Vinylmonomeren als Photokatalysator dient. Für ein bestimmtes Monomer, Einstellung einer beliebigen Anzahl von Reaktionsparameter wie Lösungsmittel, Stöchiometrie, Initiator und Lichtquelle führt zu Polymeren mit unterschiedlichen Molekulargewichten und Dispersitäten von sehr gut bis hin zu ziemlich breit. Figur 1 zeigt die Ergebnisse der Ketten- Verlängerungsexperimente wie in Teil 4 beschrieben und veranschaulicht, daß Polymere mit dieser Methode der Lage sind, gebildet als Makroinitiatoren für die weitere Polymerisation und Bildung von Block (co) Polymerisate dient. Diese Ergebnisse unterstützen gemeinsam den Schluss, dass unter den richtigen Bedingungen, Perylen ermöglicht eine Atomübertragungsradikalpolymerisation sichtbares Licht verwendet wird. Tabelle 1. Repräsentative Ergebnisse des Polymerisationsverfahrens. Wenn nicht anders angegeben, Polymerisationen wurden durchgeführt unter Verwendung von 1,00 ml Monomer und 1,00 ml des Lösungsmittels in der Tabelle angegebenen und 24 Stunden lang laufen eine weiße LED als Lichtquelle verwendet wird. Verwendeten Monomere waren Methylmethacrylat (MMA), Glycidylmethacrylat (GMA), Butylacrylat (BA), Butylmethacrylat (BMA) und Styrol (S). Initiatoren verwendet wurden ethyl α-bromphenylacetat (EBP), Methyl - α-bromisobutyrat (MBI) und Diethyl - 2-brom-2-methylmalonat (DMM). Ein Verhältnis von Monomer zu Katalysator (Perylen). B Isolierte Ausbeute zu Initiator. C Bestimmt mit Mehrwinkellichtstreuung. d für 10 Stunden durchgeführt natürliches Sonnenlicht als Lichtquelle verwendet wird . <sbis&gt; e 4,00 ml des angegebenen Lösungsmittels durchgeführt werden. <img alt="Abbildung 1" src="/files/ftp_upload/53571/53571fig1.jpg" width="700" /> Abbildung 1. Die Ergebnisse der Kettenverlängerungs Polymerisationen unter Verwendung eines poly (MMA) Makroinitiator (A) mit Butylacrylat (B), Methylmethacrylat (C), Styrol (D) und Butylmethacrylat (E). Overlaid GPC Spuren des poly (MMA) Makroinitiator (schwarz) mit Poly (MMA) -b-poly (MMA) (rot), Poly (MMA) -b-poly (BMA) (lila), Poly (MMA) -b-poly (S) ( blau) oder Poly (MMA) -b-poly (BA) (grün).

Watch this Scientific Journal Video about Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst at JoVE.com

Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst

Atomübertragungsradikalpolymerisation funktionalisierter Vinylmonomeren Mit Perylen als sichtbares Licht Photokatalysator

A method for the atom transfer radical polymerization of functionalized vinyl monomers using perylene as a visible-light photocatalyst is described.

A standardized technique for atom transfer radical polymerization of vinyl monomers using perylene as a visible-light photocatalyst is presented. The ...

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Reactions of Alkenes

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11.6K Aufrufe.  University of Colorado Boulder. A method for the atom transfer radical polymerization of functionalized vinyl monomers using perylene as a visible-light photocatalyst is described.

Serie: Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst

Exploring the Radical Nature of a Carbon Surface by Electron Paramagnetic Resonance and a Calibrated Gas Flow

While the first Electron Paramagnetic Resonance (EPR) studies regarding the effects of oxidation on the structure and stability of carbon radicals date back to the early 1980s the focus of these early papers primarily characterized the changes to the structures under extremely harsh conditions (pH or temperature)1-3. It is also known that paramagnetic molecular oxygen undergoes a Heisenberg spin exchange interaction with stable radicals that extremely broadens the EPR signal4-6. Recently, we reported interesting results where this interaction of molecular oxygen with a certain part of the existing stable radical structure can be reversibly affected simply by flowing a diamagnetic gas through the carbon samples at STP7. As flows of He, CO2, and N2 had a similar effect these interactions occur at the surface area of the macropore system.
This manuscript highlights the experimental techniques, work-up, and analysis towards affecting the existing stable radical nature in the carbon structures. It is hoped that it will help towards further development and understanding of these interactions in the community at large.

Stable radicals that are present in carbon substrates interact with paramagnetic oxygen through a Heisenberg spin exchange. This interaction can be significantly reduced under STP conditions by flowing a diamagnetic gas over the carbon system. This manuscript describes a simple method to characterize the nature of those radicals.

Exploring the Radical Nature einer Kohlenstoffoberfläche durch Elektronenspinresonanz und einem kalibrierten Gasdurchfluss

While the first Electron Paramagnetic Resonance (EPR) studies regarding the effects of oxidation on the structure and stability of carbon radicals date ...

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Chemie

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.

Synthese und Charakterisierung von funktionalisierten Metall-organische Gerüste

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

Real-time Monitoring of Reactions Performed Using Continuous-flow Processing: The Preparation of 3-Acetylcoumarin as an Example

By using inline monitoring, it is possible to optimize reactions performed using continuous-flow processing in a simple and rapid way. It is also possible to ensure consistent product quality over time using this technique. We here show how to interface a commercially available flow unit with a Raman spectrometer. The Raman flow cell is placed after the back-pressure regulator, meaning that it can be operated at atmospheric pressure. In addition, the fact that the product stream passes through a length of tubing before entering the flow cell means that the material is at RT. It is important that the spectra are acquired under isothermal conditions since Raman signal intensity is temperature dependent. Having assembled the apparatus, we then show how to monitor a chemical reaction, the piperidine-catalyzed synthesis of 3-acetylcoumarin from salicylaldehyde and ethyl acetoacetate being used as an example. The reaction can be performed over a range of flow rates and temperatures, the in-situ monitoring tool being used to optimize conditions simply and easily.

Real-time monitoring allows for fast optimization of reactions performed using continuous-flow processing. Here the preparation of 3-acetylcoumarin is used as an example. The apparatus for performing in-situ Raman monitoring is described, as are the steps required to optimize the reaction.

Echtzeit-Überwachung von Reaktionen durchgeführt mit Continuous-Flow-Verarbeitung: Die Herstellung von 3-Acetylcoumarin als Beispiel

By using inline monitoring, it is possible to optimize reactions performed using continuous-flow processing in a simple and rapid way. It is also possible ...

Using Polystyrene-block-poly(acrylic acid)-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are encapsulated in polystyrene-block-poly(acrylic acid) (PSPAA) shells and then used as monomers for their self-assembly. Spherical PSPAA micelles upon acid treatment are known to assemble into cylindrical micelles. Exploiting this tendency, the core-shell nanoparticles are induced to aggregate, coalesce, and then transform into long chains. When more than one type of nanoparticles are used, random and block &#8220;copolymers&#8221; of nanoparticles can be obtained. Detailed procedures are reported for the PSPAA encapsulation of nanoparticles, homo- and co-polymerization of the core-shell nanoparticles, separation and purification of the resulting nanoparticle chains. Transformations of single-line chains into double- and triple-line chains are also presented. The synergy between the polymer shell and the embedded nanoparticles leads to an unusual chain-growth polymerization mode, giving long nanoparticle chains that are distinct from the products of the traditional step-growth aggregation process.

Using Polystyrene-block-polyacrylic acid-coated Metal Nanoparticles as Monomers for Their Homo- and Co-polymerization

We report protocols for &#8220;polymerizing&#8221; various types of polymer-encapsulated metal nanoparticles into long chains of &#8220;homo-&#8220; and &#8220;co-polymers&#8221;.

Verwendung Polystyrol-<em&gt; Block</em&gt; -Poly (Acrylsäure) beschichteten Metallnanopartikel als Monomere für ihre Homo- und Polymerisation

We present a template-free method for &#8220;polymerizing&#8221; nanoparticles into long chains without side branches. A variety of nanoparticles are ...

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 &#945;-diimine ethylene polymerization catalyst. Initial polymerizations with the catalyst lead to optimized reaction conditions, including catalyst concentration, ethylene pressure and reaction time. Using gas-uptake data for these reactions, a procedure to calculate the initial rate of propagation (kp) is presented. Using the optimized conditions, the ability of the nickel &#945;-diimine polymerization catalyst to undergo chain transfer with diethylzinc (ZnEt2) during ethylene polymerization was investigated. A procedure to assess the ability of the catalyst to undergo chain transfer (from molecular weight and 13C NMR data), calculate the degree of chain transfer, and calculate chain transfer rates (ke) is presented.

A protocol for the high-throughput analysis of polymerization catalyst, chain transfer polymerizations, polyethylene characterization, and reaction kinetic analysis is presented.

Ethylenpolymerisationen Mit Parallel Druckreaktoren und eine kinetische Analyse 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 ...

Development of a Backbone Cyclic Peptide Library as Potential Antiparasitic Therapeutics Using Microwave Irradiation

Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is a major effort to target PPIs in basic research and in the pharmaceutical industry. Protein-protein interfaces are usually large, flat, and often lack pockets, complicating the discovery of small molecules that target such sites. Alternative targeting approaches using antibodies have limitations due to poor oral bioavailability, low cell-permeability, and production inefficiency.
Using peptides to target PPI interfaces has several advantages. Peptides have higher conformational flexibility, increased selectivity, and are generally inexpensive. However, peptides have their own limitations including poor stability and inefficiency crossing cell membranes. To overcome such limitations, peptide cyclization can be performed. Cyclization has been demonstrated to improve peptide selectivity, metabolic stability, and bioavailability. However, predicting the bioactive conformation of a cyclic peptide is not trivial. To overcome this challenge, one attractive approach it to screen a focused library to screen in which all backbone cyclic peptides have the same primary sequence, but differ in parameters that influence their conformation, such as ring size and position.
We describe a detailed protocol for synthesizing a library of backbone cyclic peptides targeting specific parasite PPIs. Using a rational design approach, we developed peptides derived from the scaffold protein Leishmania receptor for activated C-kinase (LACK). We hypothesized that sequences in LACK that are conserved in parasites, but not in the mammalian host homolog, may represent interaction sites for proteins that are critical for the parasites&#39; viability. The cyclic peptides were synthesized using microwave irradiation to reduce reaction times and increase efficiency. Developing a library of backbone cyclic peptides with different ring sizes facilitates a systematic screen for the most biological active conformation. This method provides a general, fast, and facile way to synthesize cyclic peptides.

A simple and general method for the synthesis of cyclic peptides using microwave irradiation is outlined. This procedure enables the synthesis of backbone cyclic peptides with a collection of different conformations while retaining the side chains and the pharmacophoric moieties., and therefore, allows to screen for the bioactive conformation.

Entwicklung eines Backbone zyklische Peptid-Bibliothek als potentielle Antiparasiten Therapeutics unter Mikrowellenbestrahlung

Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is ...

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.

Einfache Synthese von wurmartigen Mizellen durch sichtbares Licht Mediated Dispersion Polymerisation mit Photoredox Katalysator

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

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.

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.

Ein einfaches und effizientes Protokoll für die katalytische Insertion Polymerisation von Functional Norbornene

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

Preparation of Hollow Polystyrene Particles and Microcapsules by Radical Polymerization of Janus Droplets Consisting of Hydrocarbon and Fluorocarbon Oils

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) and fluorocarbon oil (perfluoro-n-octane, PFO) in aqueous surfactant (sodium dodecylsulfate, SDS) solutions. Since fluorocarbon oils are immiscible with hydrocarbon oils, the two oils are separated. Emulsions are prepared by stirring styrene/PFO/aqueous SDS solution mixtures at 80 &#176;C. The type of emulsions and the morphology of droplets in the emulsions are observed by light microscope and scanning confocal fluorescence microscope. It is found that oil droplets with Janus-type morphologies consisting of mutually immiscible styrene and PFO are formed in aqueous SDS solutions. Polystyrene particles are fabricated by radical polymerization of the ternary mixtures of styrene/PFO/aqueous SDS solution at 80 &#176;C. The morphologies of the polystyrene are confirmed by scanning electron microscopy and scanning transmission electron microscopy observations. These observations show the preparation of hollow polystyrene particles with a single hole on the surface. To our knowledge, this method is a novel strategy using the immiscibility of hydrocarbon and fluorocarbon oils. The hollow particles can also be applied to the preparation of microcapsules.

A protocol for the fabrication of hollow polymer particles and microcapsules by radical polymerization using emulsions consisting of styrene, perfluoro-n-octane, and aqueous SDS (sodium dodecylsulfate) solution is presented.

Vorbereitung der hohlen Polystyrol Partikel und Mikrokapseln durch radikalische Polymerisation von Janus Tröpfchen bestehend aus Kohlenwasserstoff und Fluorcarbon-Öle

In this article, we have demonstrated a method for producing hollow particles and microcapsules using oil droplets consisting of hydrocarbon oil (styrene) ...

Constructing Thioether/Vinyl Sulfide-tethered Helical Peptides Via Photo-induced Thiol-ene/yne Hydrothiolation

Here, we describe a detailed protocol for the preparation of thioether-tethered peptides using on-resin intramolecular/intermolecular thiol-ene hydrothiolation. In addition, this protocol describes the preparation of vinyl-sulfide-tethered peptides using in-solution intramolecular thiol-yne hydrothiolation between amino acids that possess alkene/alkyne side chains and cysteine residues at i, i+4 positions. Linear peptides were synthesized using a standard Fmoc-based solid-phase peptide synthesis (SPPS). Thiol-ene hydrothiolation is carried out using either an intramolecular thio-ene reaction or an intermolecular thio-ene reaction, depending on the peptide length. In this research, an intramolecular thio-ene reaction is carried out in the case of shorter peptides using on-resin deprotection of the trityl groups of cysteine residues following the complete synthesis of the linear peptide. The resin is then set to UV irradiation using photoinitiator 4-methoxyacetophenone (MAP) and 2-hydroxy-1-[4-(2-hydroxyethoxy)-phenyl]-2-methyl-1-propanone (MMP). The intermolecular thiol-ene reaction is carried out by dissolving Fmoc-Cys-OH in an N,N-dimethylformamide (DMF) solvent. This is then reacted with the peptide using the alkene-bearing residue on resin. After that, the macrolactamization is carried out using benzotriazole-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBop), 1-hydroxybenzotriazole (HoBt), and 4-Methylmorpholine (NMM) as activation reagents on the resin. Following the macrolactamization, the peptide synthesis is continued using standard SPPS. In the case of the thio-yne hydrothiolation, the linear peptide is cleaved from the resin, dried, and subsequently dissolved in degassed DMF. This is then irradiated using UV light with photoinitiator 2,2-dimethoxy-2-phenylacetophenone (DMPA). Following the reaction, DMF is evaporated and the crude residue is precipitated and purified using high-performance liquid chromatography (HPLC). These methods could function to simplify the generation of thioether-tethered cyclic peptides due to the use of the thio-ene/yne click chemistry that possesses superior functional group tolerance and good yield. The introduction of thioether bonds into peptides takes advantage of the nucleophilic nature of cysteine residues and is redox-inert relative to disulfide bonds.

We present a protocol for the construction of thioether/vinyl sulfide-tethered helical peptides using photo-induced thiol-ene/thiol-yne hydrothiolation.