Name: atom transfer radical polymerization of functionalized vinyl monomers using perylene as a visible light photocatalyst
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The authors would like to acknowledge the University of Colorado Boulder for its support of this work.

UYARI: Bu protokolde kullanılan kimyasalların çoğu tehlikeli maddelerdir. Malzeme Güvenlik Bilgi Formları (MSDS) başvurun ve bu maddelerle çalışırken uygun kişisel koruyucu ekipman (KKE) kullanın. Reaktiflerin 1. saflaştırılması, hazırlanması ve Depolama <ol><li> üreticinin protokolüne uygun bir çözücü arıtma sistemi kullanılarak kullanılacak olan çözücü saflaştınlır. Bir çözücü arıtma sistemi mevcut değilse, kurutma maddeleri (örneğin, moleküler elekler ve benzeri CAH 2) ve damıtma kullanmaktadır. Oda sıcaklığına ulaştıktan sonra eldiven kutusu içinde azot atmosferi altında, mağaza çözücüler kurutulmuştur. </li><li> üreticinin protokolüne göre yeni bir elektrik damıtılarak monomerlerin saflaştınlır. Bir kez, bir buzdolabı içinde azot atmosferi altında ışık almayan şişelerde, mağaza monomerleri damıtıldı. </li><li> üreticinin protokolüne göre yeni bir elektrik damıtılarak başlatıcılar saflaştınlır. , Mağaza başlatanlar damıtılmış kezsoğutucuda, azot atmosferi altında, koyu şişe. </li><li> üreticinin protokolüne uygun olarak, süblimleştirme yolu ile perilen saflaştınlır. süblime sonra, oda sıcaklığında benchtop perilen saklayın. </li><li> CDCI3 bir 100 g şişeye 25.0 mg BHT ilave edilerek butillenmiş hidroksitoluen döteryumlu kloroform içinde (BHT) (CDCI3) içindeki bir 250 ppm bir solüsyon hazırlamak. Hazırlayın ve benchtop bu çözüm saklayın. </li></ol> Photocatalyst olarak Perylene kullanma Metil metakrilat 2. Fotopolimerizasyon <ol><li> Tüm reaktifler oda sıcaklığına ısınmaya bırakın. Böyle renk ya da katı parçacıkların oluşumu gibi kirlenme belirtisi yok, olmadığından emin olmak için kullanmadan önce tüm reaktifleri kontrol edin. </li><li> bir nitrojen atmosferi eldiven kutusu içinde, bir 20 mL sintilasyon şişesine küçük karıştırma çubuğu yerleştirin. 2.36 mg (9.38 mmol, 1.00 eq.) Perilen ekleyin. </li><li> 1.00 mi dimetilformamid (DMF) ekleyin. </li><li> Bu karışıma, 1.00 ml (9.38 mmol ekleme1.000 eşi.), Metil metakrilat (MMA). </li><li> 1600 rpm ayarlanır ve beyaz ışık yayan diyotlar (LED&#39;ler) şeritler tarafından aydınlatılan bir heyecan plaka üzerinde şişe yerleştirin. (Örneğin, tavandaki ışıkların, yakındaki dönüş) diğer ışık kaynaklarından herhangi aydınlatma sınırlayın. </li><li> 16.4 ul ekleyin (93,8 mmol, 10.0 eq.) Reaksiyonu başlatmak için pipet aracılığıyla α-etil bromofenil asetat (EBP) evi. Not: Doğal güneş ışığını kullanarak bu reaksiyonu gerçekleştirmek için, daha sonra flakon mühür, adım 2.5 görmezden yukarıdaki adımları izleyin torpido gözünün dışarı getirmek ve doğal güneş ışığı ile aydınlatılan bir alanda şişe yerleştirin. </li><li> Sabit aydınlatma altında 24 saat için reaksiyona karıştırın. Yalıtmak ve adımları 4.1 yönergeleri izleyerek ürün poli (MMA) arındırmak - 4.4. </li></ol> Reaksiyon 3. Kinetik Analizi <ol><li> Benchtop, 2 ml&#39;lik şişe içine CDCI3 çözelti içinde BHT 0.70 ml dağıtır ve bölmeli kapak ile sağlanır. Bu şişe i getir<html> Polimerizasyon gerçekleştirildiğini torpido gözünün nto. </li><li> Reaksiyon karışımına 0.20 ml kaldırmak için bir şırınga kullanın. CDCI3 içerisinde BHT 250 ppm bir solüsyon ihtiva eden 2 ml şişe içine enjekte edilir. geri çekmek ve polimerizasyon tam söndürme sağlamak için piston birkaç kez itin. </li><li> bir NMR (Nükleer Manyetik Rezonans) Spektroskopisi tüpüne 2 ml hacimli ampullere içeriğini aktarın. Yüzde dönüşüm için 1H NMR spektroskopisi ile bu örnek analiz edin. 24 </li><li> Perilen kullanılarak metil metakrilatın polimerizasyon örnek için, reaksiyona girmemiş monomer (δ = 3.62) (M) metoksi hidrojenlerin karşılık gelen tepe noktasının altındaki alan karşılaştırarak numunenin 1H-NMR spektrumu ile yüzde dönüşümünün hesaplanması ve aşağıdaki formül kullanılarak polimer (δ = 3.50) (P) metoksi hidrojenlerin karşılık gelen tepe noktasının altındaki alan: 1 &quot;src =&quot; / files / ftp_upload / 53571 / 53571eq1.jpg &quot;/&gt; </li><li> Analizden sonra, temiz bir 20 mL sintilasyon şişesine içine NMR spektroskopisi tüp içeriğini dökün. Çözücüyü indirgenmiş basınç altında buharlaştınn. tetrahidrofuran 1.00 ml (THF) içinde örnek yeniden çözülür. </li><li> Temiz 2 mi şişeye şırınga filtre ile örnek gönder. Sayı ortalamalı moleküler ağırlık (Mn), ağırlık ortalamalı molekül ağırlığı (Mw) ve dağıtma özelliği (©) belirlenmesi için, çok açılı bir ışık saçılması bağlanmış jei girme kromatografisi (GPC) ile analiz edin. 24 </li></ol> 4. Yalıtım ve polimer ürünü saflaştırılması <ol><li> metanol 50 kat fazla içinde, reaksiyon karışımının içindekileri dökmeye ve en az 1 saat karıştırıldı izin vererek bir polimerizasyon reaksiyonu söndürmek. </li><li> üreticinin göre yeni bir elektrik süzme ile metanolden poli (metil metakrilat) izoleprotokol. Not: izolasyon yöntemi üretilen polimere bağlı olarak değişir. poli (metil metakrilat) ve polistiren için, elektrikli bir Buchner hunisi kullanılarak metanol Çökelen polimer filtre. poli (bütil akrilat) için, yapışkan polimerden metanol süzün. </li><li> ek bir 100 ml metanol ile polimerin durulayın. </li><li> Yeniden çözülür diklorometan ve tekrar polimeri yukarıda iki kez 4.3 ile 4.1 arasındaki adımları. </li></ol> Stiren ile MMA makrobaşlatıcı 5. Zincir uzatma Poli (MMA) Üretmek -b-poli (S) <ol><li> Tüm reaktifler oda sıcaklığına ısınmaya bırakın. Böyle renk ya da katı parçacıkların oluşumu gibi kirlenme belirtisi yok, olmadığından emin olmak için kullanmadan önce tüm reaktifleri kontrol edin. </li><li> bir nitrojen atmosferi eldiven kutusu içinde, poli (MMA) 136 mg (2.34 mmol, 1.00 eşi.) yer makro-başlatıcı, küçük bir karıştırma çubuğu ile donatılmış bir 20 mL sintilasyon şişesine halinde. </li><li> 0.59 mg perilen (2.34 mmol, 1.0 Ekle0 eşd.). </li><li> 1.00 ml DMF ekleyin. </li><li> 1600 rpm ayarlanır ve beyaz LED şeritleri ile aydınlatılmış bir heyecan plaka üzerinde şişe yerleştirin. (Örneğin, tavandaki ışıkların, yakındaki dönüş) diğer ışık kaynaklarından herhangi aydınlatma sınırlayın. </li><li> Bu karışıma, pipetle stiren (S) 1.24 ml (11.7 mmol, 5.000 eşi.) Ilave edin. </li><li> Sabit aydınlatma altında 24 saat için reaksiyona karıştırın. Yalıtmak ve ürün poli arındırmak (MMA) -b-poli adımlarla 4.1 yönergeleri izleyerek, (S) - 4.4. </li></ol>

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The authors have nothing to disclose.

protokol, bu polimerizasyon tekniği belirli bir örnek gösteriyor olsa da, bu reaksiyonu gerçekleştirmek araştırmacı mevcut seçenekler oldukça geniştir. Değişiklikler ATRP yapılmaktadır belirli olursa olsun photoredox optimizasyonu sağlamak için protokol boyunca noktalarının sayısı yapılabilir. inceleme altına Bu reaksiyon için yeni monomer, başlatma ve katalizörler gibi, stoikiometri ve çözücü, reaksiyon gerçekleştirmek için kullanılan ve reaksiyon koşullarının optimizasyonu bir parçası olarak yapılması gerekmektedir. Ayrıca, bireysel denemecileri gibi reaksiyon konsantrasyonu, ışık kaynağı olarak diğer parametreleri değiştirmek için bir kılavuz olarak Tablo 1 kullanmayı tercih edebilir (ister LED veya doğal güneş ışığı) ayarlamak için, ve sıcaklığı istenilen kesin sonuçlara tepki. Bu metodoloji sınırlamalar diğer ilgili polimerizasyon benzerdir. Reaksiyon oxyg duyarlıdırtr, her bir reaksiyon bileşeninin kadar kesin saflaştırma gereklidir. Bu prosedürün sonuçları tutarlı olduğu tespit değilseniz, reaktiflerin kirlenmesi büyük olasılıkla şüpheli. Daima Bölüm 1. Ayrıca açıklanan tüm reaktifler, saflaştırılmış hazırlanan ve saklanan emin olun, Bölüm 3&#39;te saflaştırma işlemi özel polimerin çözünürlük profiline göre farklı polimerlerin sentezlenmesi sırasında modifiye edilmesi gerekebilir. Son olarak, ışık akısı veya sıcaklık çok yüksek olursa, geleneksel kontrolsüz radikal polimerizasyonu ortaya dikkat etmek önemlidir. Bu sorun, bir bimodal molekül ağırlığı dağılımı ve / veya DJ, yüksek değerler (&gt; 2.0) ile gösterilebilir. Mümkün olduğunca oda sıcaklığına yakın, kabin içerisindeki sıcaklığı tutmak için bir fan kullanılması tavsiye edilir. ışık akısı çok yüksek olduğundan şüphelenilen, kullanılan LED sayısını azaltmak için ya da LED&#39;lere voltajı düşürmek için tavsiye edilir. EkDeneyler tam polimerizasyon üzerinde kontrol sağlamak için optimum ışık akısı aralığını belirlemek için halen devam etmektedir. Sonuçlar perilen oksidatif söndürme yolu ile işlevselleştirilmiş vinil monomerlerinin bir dizi radikal polimerizasyonu aracılık edebilen olduğunu göstermektedir. Kontrol deneyleri, katalizör, başlatıcı ya da ışık kaynağı, kesilen edildiği polimerizasyon işlemleri için bu bileşenlerin her üç gerekli olduğunu göstermiştir. Ilave kontrol deneyleri, aynı zamanda, hava hariç tutma teknikleri kullanımı (bu durumda, bir torpido gözü) polimerizasyon meydana gelmesine izin vermez, oksijen varlığı gibi, gerekli olduğunu göstermektedir. Bir atımlı ışık dizisi polimerizasyon durduruldu ve reaksiyonun üzerinde zamansal kontrol sağlayan, kapalı ve arka ışık kaynağı çevirerek devam edilebileceğini gösterdi. tersinir-deaktivasyon atom transfer mekanizması için destek olanlar gibi zincir uzatma deneyleri ile bulunur &lt;Tablo 1 &#39;de bulunabilir nispeten düşük © değerleri birlikte kullanıldığında, güçlü&gt; Şekil 1,., polimerizasyon photoredox bir örnek, bir ilk yanı, ATRP organocatalyzed olduğuna dair kanıtlar vardır. ATRP bu yeni tip geliştirmek ve genişletmek devam ederken, reaksiyon için birçok yeni potansiyel katalizörler, tasarım test ve optimize etmek için bir ihtiyaç olacaktır. Böyle gelecekteki çalışmalarını bu tepkileri incelemek için kullanılan yöntemler tutarlılık ve şeffaflık olduğunda yorumlamak kolay olacaktır. Burada, biz istihdam ve görünür ışık aracılı atom transfer radikal polimerizasyonu için organocatalysts değerlendirmek hangi yöntemi tebliğ.

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><tbody><tr><td>perylene, min 98.0%</td><td>TCI America</td><td>TCP0078-025G</td><td>purify by sublimation</td></tr><tr><td>&lt;em&gt;N,N&lt;/em&gt;-dimethylformamide</td><td>VWR</td><td>EM-DX1726-1</td><td>Omnisolv</td></tr><tr><td>methyl methacrylate, 99%</td><td>VWR</td><td>200000-678</td><td>distilled prior to use, stored in refrigerator</td></tr><tr><td>ethyl &amp;alpha;-bromophenyl acetate&amp;nbsp;</td><td>Aldrich</td><td>554065</td><td>distilled prior to use stored in refrigerator</td></tr><tr><td>butylated hydroxytoluene&amp;nbsp;</td><td>Aldrich</td><td>W218405</td><td></td></tr><tr><td>Chloroform-D</td><td>Cambridge Isotope Labs</td><td>DLM-7-100</td><td></td></tr><tr><td>tetrahydrofuran</td><td>VWR</td><td>EM-TX0279-1</td><td>Omnisolv</td></tr><tr><td>methanol</td><td>VWR</td><td>BDH1135</td><td></td></tr><tr><td>dichloromethane</td><td>VWR</td><td>EM-DX0831-1</td><td>Omnisolv</td></tr><tr><td>styrene, 99%</td><td>VWR</td><td>AAAA18481-0F</td><td>distilled prior to use, stored in refrigerator</td></tr><tr><td>glass scintillation vial, 20&amp;nbsp;ml</td><td>VWR</td><td>66022-065</td><td></td></tr><tr><td>screw top vial, 2 ml</td><td>Agilent</td><td>5182-0715</td><td></td></tr><tr><td>septum cap for screw top vial</td><td>Agilent</td><td>5182-0717</td><td></td></tr><tr><td>heavy wall pressure vessel, 100 ml</td><td>Synthware</td><td>P160005&amp;nbsp;</td><td></td></tr><tr><td>syringe, 1 ml norm-ject</td><td>VWR</td><td>89174-491</td><td></td></tr><tr><td>NMR tube</td><td>New Era</td><td>NE-UL5-7&#039;</td><td></td></tr><tr><td>nylon syringe filter, 0.45&amp;nbsp;&amp;#956;m</td><td>VWR</td><td>28143-240</td><td></td></tr><tr><td>glovebox</td><td>Mbraun</td><td>LABstar</td><td></td></tr><tr><td>solvent purification system</td><td>Mbraun</td><td>MB-SPS-800</td><td></td></tr><tr><td>stirplate</td><td>IKA</td><td>3582401</td><td></td></tr><tr><td>light-emitting diodes</td><td>Creative Lighting Solutions</td><td>CL-FRS1210-5M-12V-WH</td><td>2x 12-inch strips of 5500 K white LEDs were used for illumination</td></tr><tr><td>12 V DC power supply for LEDs</td><td>Creative Lighting Solutions</td><td>CL-PS16001-40W</td><td></td></tr><tr><td>high performance liquid chromatograph&amp;nbsp;</td><td>Agilent</td><td>G1310B, G1322A, G1329B, G1316A</td><td></td></tr><tr><td>gel permeation size-exclusion columns</td><td>Agilent</td><td>PL1110-6500</td><td></td></tr><tr><td>multi-angle light scattering detector</td><td>Wyatt</td><td>WTREOS</td><td></td></tr><tr><td>differential refractometer</td><td>Wyatt</td><td>WTREX</td><td></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.

Tablo 1, bu yöntem sayesinde elde polimerizasyon sonuçlarıyla aralığını göstermektedir. Bu veriler, perilen işlevselleştirilmiş vinil monomerlerinin bir dizi polimerizasyonu için bir fotokatalizör olarak hizmet kapasitesine sahip olduğunu göstermektedir. Belirli bir monomer, bu tür bir çözücü, stokiyometri, başlatma ve ışık kaynağı olarak, reaksiyon parametrelerinin herhangi bir sayıda ayarlama Şekil 1. Çok iyi oldukça geniş kadar molekül ağırlıklarına ve dispersities değişen polimerlere yol açar zincir- sonuçlarını göstermektedir yayım deneyler bölüm 4&#39;te tarif edilen, ve bu yöntemi kullanarak oluşturulan polimerler sürekli polimerizasyon ve blok (ko) polimerlerin oluşturulması için makrobaşlatıcılar olarak hizmet yeteneğine sahip olduğunu gösteriyor. Bu sonuçlar birlikte, doğru koşullar altında, penlen görünür ışık kullanarak bir atom transfer radikal polimerizasyonu kolaylaştırır sonucunu desteklemektedir. Tablo polimerizasyon prosedürü: 1. Örnek ile sonuçlanır. Aksi belirtilmedikçe, polimerizasyon, monomer 1.00 ml tabloda belirtilen ve beyaz ışık kaynağı olarak LED kullanılarak 24 saat süreyle çözücü 1.00 mi kullanılarak yapıldı. kullanılan monomerlerin metil metakrilat (MMA), glisidil metakrilat (GMA), bütil akrilat (BA), bütil metakrilat (BMA) ve stiren (S) idi. Kullanılan başlatıcılar, etil α-bromofenilasetat (EBP), metil α-bromoizobutirat (MTE) ve dietil 2-bromo-2-metilmalonat (DMM). Katalizörü (perilen) için başlatıcı monomer oranı idi. Elde edilen verim b. Kararlı Cı kullanarak çok açılı bir ışık saçılması. ışık kaynağı olarak doğal güneş ışığını kullanarak 10 saat boyunca yürütülen d. <syukarı&gt; E belirtilen çözücü 4.00 ml kullanılarak yapılmıştır. <img alt="Şekil 1" src="/files/ftp_upload/53571/53571fig1.jpg" width="700" /> Şekil bütil akrilat (B), metil metakrilat (C), stiren (D) ve butil metakrilat (E)., Poli Kaplanmış GPC ile bir poli (MMA) makro-başlatıcı, (A) kullanarak zincir uzatma polimerizasyon 1. Sonuçlar (MMA), poli (MMA) sahip makro-başlatıcı (siyah) -b-poli (MMA) (kırmızı), poli (MMA) -b-poli (BMA) (mor), poli (MMA) -b-poli (S) ( mavi) ya da poli (MMA) -b-poli (BA) (yeşil).

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

Bir görünür ışık fotokatalistinin olarak Perylene kullanarak Fonksiyonlu Vinil Monomer Atom Transfer Radikal Polimerizasyonu

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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11.6K Görüntüleme.  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.

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

Reductive Electropolymerization of a Vinyl-containing Poly-pyridyl Complex on Glassy Carbon and Fluorine-doped Tin Oxide Electrodes

Controllable electrode surface modification is important in a number of fields, especially those with solar fuels applications. Electropolymerization is one surface modification technique that electrodeposits a polymeric film at the surface of an electrode by utilizing an applied potential to initiate the polymerization of substrates in the Helmholtz layer. This useful technique was first established by a Murray-Meyer collaboration at the University of North Carolina at Chapel Hill in the early 1980s and utilized to study numerous physical phenomena of films containing inorganic complexes as the monomeric substrate. Here, we highlight a procedure for coating electrodes with an inorganic complex by performing reductive electropolymerization of the vinyl-containing poly-pyridyl complex onto glassy carbon and fluorine doped tin oxide coated electrodes. Recommendations on electrochemical cell configurations and troubleshooting procedures are included. Although not explicitly described here, oxidative electropolymerization of pyrrole-containing compounds follows similar procedures to vinyl-based reductive electropolymerization but are far less sensitive to oxygen and water.

A procedure for performing reductive electropolymerization of vinyl-containing compounds onto glassy carbon and fluorine doped tin-oxide coated electrodes is presented. Recommendations on electrochemical cell configurations and troubleshooting procedures are included. Although not explicitly described here, oxidative electropolymerization of pyrrole-containing compounds follows similar procedures to vinyl-based reductive electropolymerization.

Camsı karbon ve flüor katkılı kalay oksit elektrotlar üzerinde vinil içerikli poli-piridil Kompleksinin indirgeyici elektrokimyasal

Controllable electrode surface modification is important in a number of fields, especially those with solar fuels applications. Electropolymerization is ...

Kimya

Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties

A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step process that finishes with Negishi coupling. Negishi coupling is a cross-coupling process in which a chemical precursor is first lithiated, followed by transmetallation with ZnCl2. The resultant organozinc compound can be coupled to a dibrominated aromatic precursor to give the conjugated monomer. Polymer films can be prepared via electropolymerization of the monomer and characterized using cyclic voltammetry and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. Nanoparticles (NPs) are prepared via emulsion polymerization of the monomer using a two-surfactant system to yield an aqueous dispersion of the polymer NPs. The NPs are characterized using dynamic light scattering, electron microscopy, and UV-Vis-NIR-spectroscopy. Cytocompatibility of NPs is investigated using the cell viability assay. Finally, the NP suspensions are irradiated with a NIR laser to determine their effectiveness as potential materials for photothermal therapy (PTT).

A protocol is presented for the synthesis and preparation of nanoparticles consisting of electroactive polymers.

Elektroaktif Polimer nanopartiküller Sergileme Fototermal Özellikleri

A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step ...

Mühendislik

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.

Photoredox Katalizörü kullanarak görünür ışık aracılığı ile dispersiyon polimerleştirilmesi ile solucan gibi miseller Facile sentezi

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.

Fonksiyonel norbornenler Katalitik Yerleştirme Polimerizasyon için Basit ve Etkin Protokol

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

Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts

This paper presents a method to prepare charge-transfer chromophores using polyoxotungstate (PW12O403-), transition metal ions (Ce3+ or Co2+), and organic polymers, with the aim of photo-activating oxygen-evolving manganese oxide catalysts, which are important components in artificial photosynthesis. The cross-linking technique was applied to obtain a self-standing membrane with a high PW12O403- content. Incorporation and structure retention of PW12O403- within the polymer matrix were confirmed by FT-IR and micro-Raman spectroscopy, and optical characteristics were investigated by UV-Vis spectroscopy, which revealed successful construction of the metal-to-metal charge transfer (MMCT) unit. After deposition of MnOx oxygen evolving catalysts, photocurrent measurements under visible light irradiation verified the sequential charge transfer, Mn &#8594; MMCT unit &#8594; electrode, and&#160;the photocurrent intensity was consistent with the redox potential of the donor metal (Ce or Co). This method provides a new strategy for preparing integrated systems involving catalysts and photon-absorption parts for use with photo-functional materials.

Here, we present a protocol to prepare charge transfer chromophores based on a polyoxometalate/polymer composite membrane.

Mangan oksit katalizörler fotoğraf aktivasyonu için fotoğraf duyarlı membranlar Polyoxometalate tabanlı hazırlanması

This paper presents a method to prepare charge-transfer chromophores using polyoxotungstate (PW12O403-), transition metal ions (Ce3+ or Co2+), and organic ...

[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

Our group recently reported the use of [(DPEPhos)(bcp)Cu]PF6 as a general copper-based photoredox catalyst which proved efficient to promote the activation of a broad variety of organic halides, including unactivated ones. These can then participate in various radical transformations such as reduction and cyclization reactions, as well as in the direct arylation of several (hetero)arenes. These transformations provide a straightforward access to a range of small molecules of interest in synthetic chemistry, as well as to biologically active natural products. Altogether, [(DPEPhos)(bcp)Cu]PF6 acts as a convenient photoredox catalyst which appears to be an attractive, cheap and complementary alternative to the state-of-the-art iridium- and ruthenium-based photoredox catalysts. Here, we report a detailed protocol for the synthesis of [(DPEPhos)(bcp)Cu]PF6, as well as NMR and spectroscopic characterizations, and we illustrate its use in synthetic chemistry for the direct arylation of (hetero)arenes and radical cyclization of organic halides. In particular, the direct arylation of N-methylpyrrole with 4-iodobenzonitrile to afford&#160;4-(1-methyl-1H-pyrrol-2-yl)benzonitrile and the radical cyclization of N-benzoyl-N-[(2-iodoquinolin-3-yl)methyl]cyanamide to afford natural product luotonin A are detailed. The scope and limitations of this copper-based photoredox catalyst are also briefly discussed.

[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

Detailed and general protocols are presented for the synthesis of [(DPEPhos)(bcp)Cu]PF6, a general copper-based photoredox catalyst, and for its use in synthetic chemistry for the direct arylation of C-H bonds in (hetero)arenes and radical cyclization of organic halides.

[(DPEPhos) (bcp) cu] PF6: genel ve geniş uygulanabilir bakır bazlı Photoredox katalizörü

Our group recently reported the use of [(DPEPhos)(bcp)Cu]PF6 as a general copper-based photoredox catalyst which proved efficient to promote the ...

3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization

3D printing provides facile access to geometrically complex materials. However, these materials have intrinsically linked bulk and interfacial properties dependent on the chemical composition of the resin. In the current work, 3D printed materials are post-functionalized using the 3D printer hardware via a secondary surface-initiated polymerization process, thus providing independent control over the bulk and interfacial material properties. This process begins with preparing liquid resins, which contain a monofunctional monomer, a crosslinking multifunctional monomer, a photochemically labile species that enables initiation of polymerization, and critically, a thiocarbonylthio compound which facilitates reversible addition-fragmentation chain transfer (RAFT) polymerization. The thiocarbonylthio compound, known commonly as a RAFT agent, mediates the chain growth polymerization process and provides polymeric materials with more homogeneous network structures. The liquid resin is cured in a layer-by-layer fashion using a commercially available digital light processing 3D printer to give three-dimensional materials having spatially controlled geometries. The initial resin is removed and replaced with a new mixture containing functional monomers and photoinitiating species. The 3D printed material is then exposed to light from the 3D printer in the presence of the new functional monomer mixture. This allows photoinduced surface-initiated polymerization to occur from the latent RAFT agent groups on the surface of the 3D printed material. Given the chemical flexibility of both resins, this process allows a wide range of 3D printed materials to be produced with tailorable bulk and interfacial properties.

3D Printing and In Situ Surface Modification via Type I Photoinitiated Reversible Addition-Fragmentation Chain Transfer Polymerization

The present protocol describes the digital light processing-based 3D printing of polymeric materials using type I photoinitiated reversible addition-fragmentation chain transfer polymerization and the subsequent in situ material post-functionalization via surface-mediated polymerization. Photoinduced 3D printing provides materials with independently tailored and spatially controlled bulk and interfacial properties.

3D Baskı ve Tip I Foto-Başlatılmış Geri Dönüşümlü Ekleme-Parçalanma Zinciri Transfer Polimerizasyonu ile In Situ Yüzey Modifikasyonu

3D printing provides facile access to geometrically complex materials. However, these materials have intrinsically linked bulk and interfacial properties ...

Photochemical Initiation Of Radical Polymerization Reactions

Source: David C. Powers, Tamara M. Powers, Texas A&#38;M
In this video, we will carry out the photochemically initiated polymerization of styrene to generate polystyrene, which is an important commodity plastic. We will learn the fundamentals of photochemistry and use simple photochemistry to initiate radical polymerization reactions. Specifically, in this module we will examine the photochemistry of benzoyl peroxide and its role as a photo-initiator of styrene polymerization reactions. In the described experiments, we will investigate the role of wavelength, photon absorption, and excited state structure on the efficiency (measured as quantum yield) of photochemical reactions.

Source: David C. Powers, Tamara M. Powers, Texas A&#38;M
In this video, we will carry out the photochemically initiated polymerization of styrene to ...

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İnorganik Kimya

Free-Radical Chain Reaction and Polymerization of Alkenes

The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a repeating unit, while the terminal groups are considered insignificant. The average degree of polymerization represents the number of repeating units in the polymer molecule and is denoted by the subscript n.
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Alkenes undergo polymerization via a free-radical mechanism involving three steps: initiation, propagation, and termination.&#160;
Radicals are generated in the initiation step by heating a small quantity of free-radical initiators such as benzoyl peroxide. The benzoyloxy radical loses CO2 and forms a phenyl radical (Ph&#183;), which adds to the double bond of the alkene to initiate the polymerization process. One of the electrons of the alkene &#960; bond pairs with one electron from the phenyl radical to form a new C&#8211;C bond.
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In the propagation step, the carbon radical generated in the initiation step adds to another molecule of alkene to generate a new radical. The continuous addition of alkene monomers at the radical site yields the polymer.
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The termination step of the free-radical mechanism occurs via recombination or disproportionation. In a recombination step, two growing chains form a bond at their radical sites.
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In termination by disproportionation, a &#946;-hydrogen atom is transferred from one radical to another radical center, resulting in two non-radical products.
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The free-radical polymerization of ethylene yields low-density polyethylene (LDPE), where the low density is a consequence of significant branching in the polymer chains. Articles made from polymers surround us in various forms, such as food packaging materials, plastic bags, bottles, stationery, and automotive parts.

Free-radical Polymerization Reaction of Alkenes

Serbest Radikal Zincir Reaksiyonu ve Alkenlerin Polimerizasyonu

The conversion of alkenes to macromolecules called polymers is a reaction of high commercial importance. The structure of the polymer is defined by a ...

Organik Kimya

Alkenlerin Tepkimeleri

KEY TERMS AND CONCEPTS

Radical Chain-Growth Polymerization: Overview

Chain-growth or addition polymerization is successive addition reactions of monomers with a polymer chain. In radical chain-growth polymerization, the reaction proceeds via a free-radical intermediate. The free radical is formed from radical initiators, which spontaneously generate free radicals by homolytic fission. Organic peroxides (such as dibenzoyl peroxide, as shown in Figure 1) or azo compounds are popular radical initiators. A low concentration ratio of radical initiator to monomer is used to minimize radical coupling.
<img alt="Figure1" src="/files/ftp_upload/12920/12920_PT_Figure_1.svg" style="text-align: center; height: 75px;" />
Figure 1: The homolytic fission reaction of radical initiator dibenzoyl peroxide to generate benzoyloxy radicals and the subsequent decomposition to phenyl radicals
This free radical initiates polymerization by reacting with a monomer molecule. Unsaturated monomers are suitable for radical chain-growth polymerization; a substituent group across the unsaturated bond that stabilizes the free radical increases the reaction feasibility. Ethylene, propylene, vinyl chloride, and styrene are examples of monomers that can be polymerized via free-radical chain-growth polymerization.
The reaction between a monomer and a free radical generates a new free radical. This new radical reacts with another monomer and creates yet another free radical. The polymer chain grows as the reaction between free-radical intermediates and monomers repeats sequentially. Typically, the propagation step repeats one thousand to ten thousand times before the termination of polymerization.
Often, chain transfer reagents, such as thiol, are used to control the molecular weight (Figure 2). A chain transfer agent must be sufficiently reactive to transfer a hydrogen atom to the growing chain to terminate the polymer growth. The resultant radical must add to a double bond in the monomer to initiate polymerization.
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Figure 2: (Top): The termination reaction of chain transfer agent thiol and a growing polymer chain; (Bottom): Subsequent reaction of thiol radical and monomer molecule to initiate polymer growth
Inhibitors are the reagents used to reduce the reactivity of radicals in the growing polymer chain. Figure 3 depicts the reaction of benzoquinone as an inhibitor.
<img alt="Figure3" src="/files/ftp_upload/12920/12920_PT_Figure_3.svg" style="text-align: center; height: 200px;" />
Figure 3: The reaction between chain inhibitor benzoquinone and a growing polymer chain to generate a less reactive free radical

Radikal Zincir Büyüme Polimerizasyonu: Genel Bakış

Chain-growth or addition polymerization is successive addition reactions of monomers with a polymer chain. In radical chain-growth polymerization, the ...