Name: [(dpephos)(bcp)cu]pf6: a general and broadly applicable copper-based photoredox catalyst
Uploaded: 2019-05-21T14:45:00
Description: Watch this Scientific Journal Video about [DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst at JoVE.com

This work was supported by the Universit&#233; libre de Bruxelles (ULB), the F&#233;d&#233;ration Wallonie-Bruxelles (ARC Consolidator 2014-2019), Innoviris (project PhotoCop), and the COST action CM1202. H.B. acknowledges the Fonds pour la formation &#224; la Recherche dans l&#8217;Industrie et dans l&#8217;Agriculture (F.R.I.A.) for graduate fellowship. C.T. acknowledges the Fonds de la Recherche Scientifique (FNRS) for research fellowship.

1. Synthesis of [(DPEPhos)(bcp)Cu]PF6
<ol>
	<li>Add 3.73 g (10.00 mmol) of tetrakisacetonitrile copper(I) hexafluorophosphate and 5.39 g (10.00 mmol) of DPEPhos to a 2 L round bottom flask equipped with a magnetic stir bar.</li>
	<li>Fit the round bottom flask with a three neck vacuum adapter connected to a vacuum line and an argon line.</li>
	<li>Evacuate the flask under vacuum and backfill with argon three times. Replace the three neck vacuum adapter by a rubber septum. 
	NOTE: The reaction can be per...

<ol>
	<li>Chatgilialoglu, C., Studer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Encyclopedia of Radicals in Chemistry, Biology and Materials. , (2012).</li><li>Narayanam, J. M. R., Stephenson, C. R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visible+light+photoredox+catalysis:+applications+in+organic+synthesis.">Visible light photoredox catalysis: applications in organic synthesis.</a> Chemical Society Reviews. 40, 102-113 (2011).</li><li>Prier, C. K., Rankic, D. A., MacMillan, D. W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visible+Light+Photoredox+Catalysis+with+Transition+Metal+Complexes:+Applications+in+Organic+Synthesis.">Visible Light Photoredox Catalysis with Transition Metal Complexes: Applications in Organic Synthesis.</a> Chemical Reviews. 113 (7), 5322-5363 (2013).</li><li>Romero, N. A., Nicewicz, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organic+Photoredox+Catalysis.">Organic Photoredox Catalysis.</a> Chemical Reviews. 116 (17), 10075 (2016).</li><li>Paria, S., Reiser, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Copper+in+Photocatalysis.">Copper in Photocatalysis.</a> ChemCatChem. 6 (9), 2477-2483 (2014).</li><li>Reiser, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shining+Light+on+Copper:+Unique+Opportunities+for+Visible-Light-Catalyzed+Atom+Transfer+Radical+Addition+Reactions+and+Related+Processes.">Shining Light on Copper: Unique Opportunities for Visible-Light-Catalyzed Atom Transfer Radical Addition Reactions and Related Processes.</a> Accounts of Chemical Research. 49 (9), 1990-1996 (2016).</li><li>Boyer, C., 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=Copper-Mediated+Living+Radical+Polymerization+(Atom+Transfer+Radical+Polymerization+and+Copper(0)+Mediated+Polymerization):+From+Fundamentals+to+Bioapplications.">Copper-Mediated Living Radical Polymerization (Atom Transfer Radical Polymerization and Copper(0) Mediated Polymerization): From Fundamentals to Bioapplications.</a> Chemical Reviews. 116 (4), 1803-1949 (2016).</li><li>Paria, S., Reiser, O., Stephenson, C. R. J., Yoon, T. P., MacMillan, D. W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visible+Light+and+Copper+Complexes:+A+Promising+Match+in+Photoredox+Catalysis.">Visible Light and Copper Complexes: A Promising Match in Photoredox Catalysis.</a> Visible Light Photocatalysis in Organic Chemistry. , 233-252 (2018).</li><li>Grutsch, P. A., Kutal, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photobehavior+of+copper(I)+compounds.+Role+of+copper(I)-phosphine+compounds+in+the+photosensitized+isomerization+of+norbornadiene.">Photobehavior of copper(I) compounds. Role of copper(I)-phosphine compounds in the photosensitized isomerization of norbornadiene.</a> Journal of the American Chemical Society. 101 (15), 4228-4233 (1979).</li><li>Mitani, M., Kato, I., Koyama, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoaddition+of+alkyl+halides+to+olefins+catalyzed+by+copper(I)+complexes.">Photoaddition of alkyl halides to olefins catalyzed by copper(I) complexes.</a> Journal of the American Chemical Society. 105 (22), 6719-6721 (1983).</li><li>Kern, J. -. M., Sauvage, J. -. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoassisted+C-C+coupling+via+electron+transfer+to+benzylic+halides+by+a+bis(di-imine)+copper(I)+complex.">Photoassisted C-C coupling via electron transfer to benzylic halides by a bis(di-imine) copper(I) complex.</a> Journal of the Chemical Society, Chemical Communications. , 546-548 (1987).</li><li>Creutz, S. E., Lotito, K. J., Fu, G. C., Peters, 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=Photoinduced+Ullmann+C-N+coupling:+demonstrating+the+viability+of+a+radical+pathway.">Photoinduced Ullmann C-N coupling: demonstrating the viability of a radical pathway.</a> Science. 338 (6107), 647-651 (2012).</li><li>Kainz, Q. M., Matier, C. D., Bartoszewicz, A., Zultanski, S. L., Peters, J. C., Fu, G. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Asymmetric+copper-catalyzed+C-N+cross-couplings+induced+by+visible+light.">Asymmetric copper-catalyzed C-N cross-couplings induced by visible light.</a> Science. 351 (6274), 681-684 (2016).</li><li>Matier, C. D., Schwaben, J., Peters, J. C., Fu, G. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Copper-Catalyzed+Alkylation+of+Aliphatic+Amines+Induced+by+Visible+Light.">Copper-Catalyzed Alkylation of Aliphatic Amines Induced by Visible Light.</a> Journal of the American Chemical Society. 139 (49), 17707-17710 (2017).</li><li>He, J., Chen, C., Fu, G. C., Peters, 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=Visible-Light-Induced,+Copper-Catalyzed+Three-Component+Coupling+of+Alkyl+Halides,+Olefins+and+Trifluoromethylthiolate+to+Generate+Trifluoromethyl+Thioethers.">Visible-Light-Induced, Copper-Catalyzed Three-Component Coupling of Alkyl Halides, Olefins and Trifluoromethylthiolate to Generate Trifluoromethyl Thioethers.</a> ACS Catalysis. 8 (12), 11741-11748 (2018).</li><li>Pirtsch, M., Paria, S., Matsuno, T., Isobe, H., Reiser, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=[Cu(dap)2Cl]+As+an+Efficient+Visible-Light-Driven+Photoredox+Catalyst+in+Carbon-Carbon+Bond-Forming+Reactions.">[Cu(dap)2Cl] As an Efficient Visible-Light-Driven Photoredox Catalyst in Carbon-Carbon Bond-Forming Reactions.</a> Chemistry - A European Journal. 18 (24), 7336-7340 (2012).</li><li>Paria, S., Pirtsch, M., Kais, V., Reiser, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visible-Light-Induced+Intermolecular+Atom-Transfer+Radical+Addition+of+Benzyl+Halides+to+Olefins:+Facile+Synthesis+of+Tetrahydroquinolines.">Visible-Light-Induced Intermolecular Atom-Transfer Radical Addition of Benzyl Halides to Olefins: Facile Synthesis of Tetrahydroquinolines.</a> Synthesis. 45 (19), 2689-2698 (2013).</li><li>Knorn, M., Rawner, T., Czerwieniec, R., Reiser, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=[Copper(phenanthroline(bisisonitrile)]+-Complexes+for+the+Visible-Light-Mediated+Atom+Transfer+Radical+Addition+and+Allylation+Reactions.">[Copper(phenanthroline(bisisonitrile)]+-Complexes for the Visible-Light-Mediated Atom Transfer Radical Addition and Allylation Reactions.</a> ACS Catalysis. 5 (9), 5186-5193 (2015).</li><li>Bagal, D. B., Kachkovskyi, G., Knorn, M., Rawner, T., Bhanage, B. M., Reiser, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trifluoromethylchlorosulfonylation+of+Alkenes:+Evidence+for+an+Inner-Sphere+Mechanism+by+a+Copper+Phenanthroline+Photoredox+Catalyst.">Trifluoromethylchlorosulfonylation of Alkenes: Evidence for an Inner-Sphere Mechanism by a Copper Phenanthroline Photoredox Catalyst.</a> Angewandte Chemie International Edition. 54 (24), 6999-7002 (2015).</li><li>Hossain, 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=Visible-Light-Accelerated+Copper(II)-Catalyzed+Regio-+and+Chemoselective+Oxo-Azidation+of+Vinyl+Arenes.">Visible-Light-Accelerated Copper(II)-Catalyzed Regio- and Chemoselective Oxo-Azidation of Vinyl Arenes.</a> Angewandte Chemie International Edition. 57 (27), 8288-8292 (2018).</li><li>Hernandez-Perez, A. C., Vlassova, A., Collins, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toward+a+Visible+Light+Mediated+Photocyclization:+Cu-Based+Sensitizers+for+the+Synthesis+of+[5]Helicene.">Toward a Visible Light Mediated Photocyclization: Cu-Based Sensitizers for the Synthesis of [5]Helicene.</a> Organic Letters. 14 (12), 2988-2991 (2012).</li><li>Baralle, A., Fensterbank, L., Goddard, J. -. P., Ollivier, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aryl+Radical+Formation+by+Copper(I)+Photocatalyzed+Reduction+of+Diaryliodonium+Salts:+NMR+Evidence+for+a+CuII/CuI+Mechanism.">Aryl Radical Formation by Copper(I) Photocatalyzed Reduction of Diaryliodonium Salts: NMR Evidence for a CuII/CuI Mechanism.</a> Chemistry - A European Journal. 19 (23), 10809-10813 (2013).</li><li>Hernandez-Perez, A. C., Collins, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Visible-Light-Mediated+Synthesis+of+Carbazole.">A Visible-Light-Mediated Synthesis of Carbazole.</a> Angewandte Chemie International Edition. 52 (48), 12696-12700 (2013).</li><li>Tang, X. -. J., Doldier, W. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+Cu-catalyzed+Atom+Transfer+Radical+Addition+Reactions+of+Fluoroalkylsulfonyl+Chlorides+with+Electron-Deficient+Alkenes+Induced+by+Visible+Light.">Efficient Cu-catalyzed Atom Transfer Radical Addition Reactions of Fluoroalkylsulfonyl Chlorides with Electron-Deficient Alkenes Induced by Visible Light.</a> Angewandte Chemie International Edition. 54 (14), 4246-4249 (2015).</li><li>Fumagalli, G., Rabet, P. T. G., Boyd, S., Greaney, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-Component+Azidation+of+Styrene-Type+Double+Bonds:+Light-Switchable+Behavior+of+a+Copper+Photoredox+Catalyst.">Three-Component Azidation of Styrene-Type Double Bonds: Light-Switchable Behavior of a Copper Photoredox Catalyst.</a> Angewandte Chemie International Edition. 54 (39), 11481-11484 (2015).</li><li>Demmer, C. S., Benoit, E., Evano, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+Allenamides+by+Copper-Catalyzed+Coupling+of+Propargylic+Bromides+and+Nitrogen+Nucleophiles.">Synthesis of Allenamides by Copper-Catalyzed Coupling of Propargylic Bromides and Nitrogen Nucleophiles.</a> Organic Letters. 18 (6), 1438-1441 (2016).</li><li>Theunissen, C., Wang, J., Evano, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Copper-catalyzed+direct+alkylation+of+heteroarenes.">Copper-catalyzed direct alkylation of heteroarenes.</a> Chemical Science. 8, 3465-3470 (2017).</li><li>Michelet, B., Deldaele, C., Kajouj, S., Moucheron, C., Evano, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+General+Copper+Catalyst+for+Photoredox+Transformations+of+Organic+Halides.">A General Copper Catalyst for Photoredox Transformations of Organic Halides.</a> Organic Letters. 19 (13), 3576-3579 (2017).</li><li>Baguia, H., Deldaele, C., Romero, E., Michelet, B., Evano, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Copper-Catalyzed+Photoinduced+Radical+Domino+Cyclization+of+Ynamides+and+Cyanamides:+A+Unified+Entry+to+Rosettacin,+Luotonin+A,+and+Deoxyvasicinone.">Copper-Catalyzed Photoinduced Radical Domino Cyclization of Ynamides and Cyanamides: A Unified Entry to Rosettacin, Luotonin A, and Deoxyvasicinone.</a> Synthesis. 50 (15), 3022-3030 (2018).</li><li>Deldaele, C., Michelet, B., Baguia, H., Kajouj, S., Romero, E., Moucheron, C., Evano, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+General+Copper-based+Photoredox+Catalyst+for+Organic+Synthesis:+Scope+Application+in+Natural+Product+Synthesis+and+Mechanistic+Insights.">A General Copper-based Photoredox Catalyst for Organic Synthesis: Scope Application in Natural Product Synthesis and Mechanistic Insights.</a> CHIMIA. 72 (9), 621-629 (2018).</li><li>Luo, S. -. P., 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=Photocatalytic+Water+Reduction+with+Copper-Based+Photosensitizers:+A+Noble-Metal-Free+System.">Photocatalytic Water Reduction with Copper-Based Photosensitizers: A Noble-Metal-Free System.</a> Angewandte Chemie International Edition. 52 (1), 419-423 (2013).</li><li>Gryko, D. T., Vakuliuk, O., Gryko, D., Koszarna, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Palladium-Catalyzed+2-Arylation+of+Pyrroles.">Palladium-Catalyzed 2-Arylation of Pyrroles.</a> The Journal of Organic Chemistry. 74 (24), 9517-9520 (2009).</li><li>Servais, A., Azzouz, M., Lopes, D., Courilon, C., Malacria, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radical+Cyclization+of+N-Acylcyanamides:+Total+Synthesis+of+Luotonin+A.">Radical Cyclization of N-Acylcyanamides: Total Synthesis of Luotonin A.</a> Angewandte Chemie International Edition. 46 (4), 576-579 (2007).</li><li>Cambi&#233;, D., Bottecchia, C., Straathof, N. J. W., Hessel, V., No&#235;l, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applications+of+Continuous-Flow+Photochemistry+in+Organic+Synthesis,+Material+Science,+and+Water+Treatment.">Applications of Continuous-Flow Photochemistry in Organic Synthesis, Material Science, and Water Treatment.</a> Chemical Reviews. 116 (17), 10276-10341 (2016).</li><li>Straathof, N. J. W., No&#235;l, T., Stephenson, C. R. J., Yoon, T. P., MacMillan, D. W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Accelerating+Visible-Light+Photoredox+Catalysis+in+Continuous-Flow+Reactors.">Accelerating Visible-Light Photoredox Catalysis in Continuous-Flow Reactors.</a> Visible Light Photocatalysis in Organic Chemistry. , 389-413 (2018).</li><li>Marion, F., Courillon, C., Malacria, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radical+Cyclization+Cascade+Involving+Ynamides:+An+Original+Access+to+Nitrogen-Containing+Heterocycles.">Radical Cyclization Cascade Involving Ynamides: An Original Access to Nitrogen-Containing Heterocycles.</a> Organic Letters. 5 (26), 5095-5097 (2003).</li><li>Han, Y. -. Y., Jiang, H., Wang, R., Yu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+Tetracyclic+Quinazolinones+Using+a+Visible-Light-Promoted+Radical+Cascade+Approach.">Synthesis of Tetracyclic Quinazolinones Using a Visible-Light-Promoted Radical Cascade Approach.</a> The Journal of Organic Chemistry. 81 (16), 7276-7281 (2016).</li></ol>

Synthesis of [(DPEPhos)(bcp)Cu]PF6 
The synthesis of [(DPEPhos)(bcp)Cu]PF6 is typically performed using dry dichloromethane (distilled prior to use) and under argon to ensure the highest yield, purity and good reproducibility. As mentioned in the protocol, the synthesis of [(DPEPhos)(bcp)Cu]PF6 can be performed with regular dichloromethane (99.8%) and/or under air with variable efficiencies. Indeed, while the use of regular dichloromethane under argon afforded the sa...

Radical transformations have been known for decades to provide remarkably efficient pathways in synthetic chemistry which are often complementary to transformations based on cationic, anionic or pericyclic processes1. While particularly promising for various types of transformations, radical-based chemistry has however long been underexploited, mainly because of the need for highly toxic reagents which considerably limits its attractiveness. Moreover, radical processes have long been considered as transformations associated with poor levels of control in terms of regio- and/or stereoselectivity, or leading to extensive dimerization and/or polymerization issues.
Alternative strategies have recently been developed in order to facilitate the generation and better control the reactivity of radical species. Among them, photoredox catalysis has become one of the most powerful methods as it allows the convenient generation of radical species using a light-responsive compound, namely the photoredox catalyst, and visible light irradiation2,3. Visible light itself is indeed able to promote population of the excited state of the photoredox catalyst which becomes, consequently, both a stronger reductant and oxidant than in its corresponding ground state. These enhanced redox properties make single-electron transfer processes, not feasible in the ground state, possible under mild conditions from the excited state. Over the past decade, visible light photoredox catalysis has become an attractive and powerful technique in organic synthesis and has allowed the development of numerous remarkably efficient and selective transformations based on radical intermediates generated under sustainable, mild and user-friendly conditions.
While most photoredox processes reported to date are dominated by the use of iridium- and ruthenium-based photoredox catalysts, as well as by some organic dyes such as pyrylium and acridinium derivatives4, cheaper alternatives are still highly demanded for the development of complementary processes of interest for industrial applications. In this regard, the use of copper-based photoredox catalysts appears particularly appealing as they are not only cheaper but also provide opportunities to activate a broader and/or different range of substrates, which therefore opens new perspectives in photoredox catalysis5,6,7,8. Despite some promising early works reported by the Kutal9, Mitani10&#160;and Sauvage11&#160;groups, photoactivatable copper complexes have, however, only been scarcely used in photoredox catalysis, most probably because of their short-lived excited states compared to their ruthenium- and iridium-based congeners. More recently, recent remarkable contributions by Peters and Fu12,13,14,15, Reiser16,17,18,19,20&#160;and other groups21,22,23,24,25&#160;have clearly brought attention back to copper-based photoredox catalysts and demonstrated their unique potential.
As part of our recent interest in copper-catalyzed radical processes26,27, we recently reported a general and broadly applicable copper-based photoredox catalyst, [(DPEPhos)(bcp)Cu]PF6 (DPEPhos: bis[(2-diphenylphosphino)phenyl] ether; bcp: bathocuproine), which turned out to be particularly efficient for the activation of organic halides under visible light irradiation (Figure 1A)28,29,30. Upon irradiation with visible light and in the presence of an amine as sacrificial reductant, a wide range of unactivated aryl and alkyl halides was shown to be easily activated by catalytic amounts of [(DPEPhos)(bcp)Cu]PF6 and therefore to participate in various radical transformations including reductions, cyclizations and direct arylation of several electron-rich (hetero)arenes. Furthermore, [(DPEPhos)(bcp)Cu]PF6 has also proven successful at promoting photoinduced radical domino cyclizations of ynamides and cyanamides, providing an efficient and straightforward access to complex tri-, tetra- and pentacyclic nitrogen heterocycles at the core structures of various natural products. This strategy permitted the efficient synthesis of rosettacin, luotonin A, and deoxyvasicinone, natural products that exhibit anticancer, antimicrobial, anti-inflammatory and antidepressant activities. These transformations are illustrated in Figure 1C. From a mechanistic standpoint, the photoinduced activation of organic halides with [(DPEPhos)(bcp)Cu]PF6 proceeds through a rare Cu(I)/Cu(I)*/Cu(0) catalytic cycle, which has been confirmed by extensive mechanistic and photophysical studies. In particular, excitation of the ground state [(DPEPhos)(bcp)Cu]PF6 [Cu(I)] upon irradiation by visible light leads to the formation of the corresponding excited complex [(DPEPhos)(bcp)Cu]PF6* [Cu(I)*] which is then reduced by the sacrificial amine to generate the corresponding [(DPEPhos)(bcp)Cu]PF6 [Cu(0)] species. This Cu(0) intermediate is reductive&#160;enough to reduce the carbon&#8211;halogen bond of various organic halides to generate the corresponding radicals, which can then participate in the aforementioned transformations, together with regeneration of the starting catalyst (Figure 1B).
In the following section, we first describe the protocol to synthesize the photoactivatable [(DPEPhos)(bcp)Cu]PF6 (whose NMR and spectroscopic characterizations are presented in the representative results section). The synthesis is straightforward and particularly convenient, and simply requires addition of 1 equivalent of DPEPhos and 1 equivalent of bcp to a solution of tetrakisacetonitrile copper(I) hexafluorophosphate in dichloromethane. The desired [(DPEPhos)(bcp)Cu]PF6 is then isolated by precipitation from diethyl ether and can be easily obtained on a multigram scale (Figure 2A). Importantly, the isolated copper complex is not particularly sensitive to oxygen and moisture and can therefore be conveniently handled with no specific precautions other than being stored away from light.
Secondly, we describe the protocols to activate organic halides using [(DPEPhos)(bcp)Cu]PF6 under visible light irradiation by focusing on two different transformations. The first reaction is the direct arylation of N-methylpyrrole with 4-iodobenzonitrile using catalytic amounts of [(DPEPhos)(bcp)Cu]PF6 as photoredox catalyst, dicyclohexylisobutylamine as the sacrificial reductant and potassium carbonate as the base under irradiation at 420 nm (Figure 2B). The second reaction is the radical cyclization of N-benzoyl-N-[(2-iodoquinolin-3-yl)methyl]cyanamide, using the same catalyst and sacrificial reductant, whose cyclization directly leads to luotonin A, a natural product displaying interesting anticancer activities (Figure 2C). Detailed protocols are provided for both transformations.

<table border="0" cellpadding="0" cellspacing="0" style="width:572px;" width="573">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Material</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Bathocuproine (bcp)</td>
			<td style="width:71px;">Acros</td>
			<td style="width:119px;">161340010</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Acetonitrile, 99.9+</td>
			<td style="width:71px;">Acros</td>
			<td style="width:119px;">326811000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Celite 545</td>
			<td style="width:71px;">Acros</td>
			<td style="width:119px;">349670025</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Bis[(2-diphenylphosphino)phenyl] ether (DPEphos)</td>
			<td style="width:71px;">Acros</td>
			<td style="width:119px;">383370050</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Calcium hydride</td>
			<td style="width:71px;">Acros</td>
			<td style="width:119px;">C/1620/48</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Dichloromethane, 99.8%</td>
			<td style="width:71px;">Fisher Chemical</td>
			<td style="width:119px;">D/1852/25</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Dietyl ether, &#62;= 99%</td>
			<td style="width:71px;">Fisher Chemical</td>
			<td style="width:119px;">D/2400/MS21</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Ethyl acetate</td>
			<td style="width:71px;">Fisher Chemical</td>
			<td style="width:119px;">E/0900/25</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">N-Methylpyrrole, 99%</td>
			<td style="width:71px;">Sigma Aldrich</td>
			<td style="width:119px;">M78801</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">4-Iodobenzonitrile, 98%</td>
			<td style="width:71px;">Combi-Blocks</td>
			<td style="width:119px;">OR-3151</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Petroleum ether (40-60 &#176;)</td>
			<td style="width:71px;">Fisher Chemical</td>
			<td style="width:119px;">P/1760/25</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Potassium carbonate, anhydrous</td>
			<td style="width:71px;">Fisher Chemical</td>
			<td style="width:119px;">P/4120/60</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Tetrakisacetonitrile copper(I) hexafluorophosphate, 97%</td>
			<td style="width:71px;">Sigma Aldrich</td>
			<td style="width:119px;">346276</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Equipment</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">1H and 13C NMR spectrometer</td>
			<td style="width:71px;">Bruker</td>
			<td style="width:119px;">Avance 300 Spectrometer</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">1H and 13C NMR spectrometer</td>
			<td style="width:71px;">Varian</td>
			<td style="width:119px;">VNMRS 400 Spectrometer</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">420 nm light tubes</td>
			<td style="width:71px;">Luzchem</td>
			<td style="width:119px;">LZC-420</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Blue LEDs lamp</td>
			<td style="width:71px;">Kessil</td>
			<td style="width:119px;">H150-Blue</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Blue LEDs strips</td>
			<td style="width:71px;">Eglo</td>
			<td style="width:119px;">92065</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Photochemistry Device PhotoRedOx Box</td>
			<td style="width:71px;">Hepatochem</td>
			<td style="width:119px;">HCK1006-01-016</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Photoreactor</td>
			<td style="width:71px;">Luzchem</td>
			<td style="width:119px;">CCP-4V</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Spectrofluorimeter</td>
			<td style="width:71px;">Shimadzu</td>
			<td style="width:119px;">RF-5301PC</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">UV/Vis spectrometer</td>
			<td style="width:71px;">Perkin Elmer</td>
			<td style="width:119px;">Lambda 40</td>
			<td></td>
		</tr>
	</tbody>
</table>

[(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.

Synthesis of [(DPEPhos)(bcp)Cu]PF6 
As shown by the protocol described in the above section, the synthesis of [(DPEPhos)(bcp)Cu]PF6 is particularly convenient and can be easily performed on a multigram scale. The 1H and 13C NMR spectra indicate formation of the pure complex (Figure 4A,B). The spectroscopic data correspond to those previously reported31.
...

Watch this Scientific Journal Video about [DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst at JoVE.com

[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: 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 ...

Photoredox catalysis has emerged over the past decade as one of the most efficient methods to promote radical processes. It is indeed especially easy to implement, user-friendly, highly sustainable, and also it does not rely on the use of toxic or hazardous reagents that are usually used in radical chemistry. The main principle of photoredox catalysis is very simple, since, as you can tell by the name, it is based on the use of light-responsive compound called the photoredox catalyst that can be easily activated by irradiation with visible light in order to initiate the catalytic cycle.Among all photoredox catalysts that have been reported and utilized to date, most of them are actually based on ruthenium and iridium complexes which pose a rather strong limitation due to the high prices. As a consequence, the development of alternative photoredox catalysts that are based on cheaper and non-noble metals such as copper is therefore highly important not only for the development of less expensive systems but also for new applications. This was a main motivation when we started the synthesis and the development of this new copper-based photoredox catalyst whose synthesis is presented in this video together with synthetic applications.In addition to the role for chemical syntheis, copper-based catalysts could also play a role in photocatalysis, for instance, in a water reduction or carbon dioxide reduction which is very important for clean energy production and storage and also for the pollution. The procedures will be demonstrated by two PhD students from my lab, Ms.Hajar Baguia and Mr.Jerome Beaudelot. To begin, add 10 millimoles of tetrakisacetonitrile copper(I)hexafluorophosphate and 10 millimoles of DPEPhos to a two liter round bottom flask equipped with a magnetic stir bar.Fit the round bottom flask with a three neck vacuum adapter connected to a vacuum line and a balloon filled with argon. Turn the adapter to evacuate the flask for one minute and then turn it again to backfill the flask with argon. Repeat this cycle two times.Replace the three neck vacuum adapter by a rubber septum with a balloon of argon. Through a needle, add 800 milliliters of distilled dichloromethane and wrap the flask with aluminum foil to block light. Place the flask on a magnetic stirrer and stir the reaction mixture for two hours at approximately 23 to 25 degrees Celsius under the argon atmosphere.After that, add 10 millimoles of bcp to a 500 milliliter round bottom flask equipped with a magnetic stir bar. Fit the round bottom flask with a three neck vacuum adapter connected to a vacuum line and a balloon filled with argon. Evacuate the flask under vacuum and backfill with argon three times.Replace the three neck vacuum adapter by a rubber septum with a balloon of argon. Through a needle, add 200 milliliters of distilled dichloromethane and gently stir the suspension until complete dissolution of the bcp. Equip a cannula to the two rubber septa on the two liter and 500 milliliter flasks with the end of the canula submerged in the solution in the 500 milliliter flask.Remove the balloon of argon from the two liter flask to transfer the whole content of the smaller flask to the bigger flask. Then, put the balloon of argon back on the two liter flask. Stir for an additional hour in the dark at approximately 23 to 25 degrees Celsius under an argon atmosphere.Next, place a pad of celite in a fritted funnel on top of a flask and filter the mixture. Wash with approximately 100 milliliters of distilled dichloromethane. Then, place the flask on a rotary evaporator to concentrate the filtrate to a volume between 50 to 100 milliliters under reduced pressure.Use an addition funnel to add the concentrate drop-wise to one liter of diethyl ether on a magnetic stirrer with vigorous stirring to induce precipitation of the desired complex. Now, collect the precipitate by filtration through a fritted funnel with a pore size of three micrometers on top of a Buchner flask and wash the precipitate with approximately 100 milliliters of diethyl ether. Dry the bright yellow precipitate under vacuum at room temperature for five hours to recover 10.1 grams equaling 91%yield of the copper complex.First, in an oven-dried 10 milliliter vial, add 0.05 millimoles of the synthesized catalyst, 0.25 millimoles of dicyclohexyl isobutylamine, one millimole of potassium carbonate, and 0.5 millimoles of 4-iodobenzonitrile. Place a magnetic stir bar. Seal the vial with rubber septum.Connect the vial to a rubber line connecting to vacuum, evacuate the vial under vacuum for 30 seconds, and backfill with argon three times. Then, through the septum, add five milliliters of freshly distilled and degassed acetonitrile and 890 microliters of n-methylpyrrole to the vial. Replace the rubber septum by a screw cap.Place the vial in a photoreactor under 420-nanometer-wavelength irradiation and stir the reaction mixture for three days at approximately 23 to 25 degrees Celsius. Blue LED strips or a blue LED lamp at 440 nanometers and 34 watts can be used instead. After three days, filter the reaction mixture through a pad of celite.Wash with approximately five milliliters of diethyl ether and concentrate the filtrate under reduced pressure on a rotary evaporator. Next, dissolve the concentrate with the minimum amount of solvent and place it on top of a column chromatography to start purifying the crude residue over silica gel. After that, place the content of all tubes containing the pure product in a flask and concentrate on a rotary evaporator.Place the flask on a vacuum line to dry the pure compound at room temperature for three hours in order to recover 65 milligrams equaling 72%healed of the desired C2 arylated pyrrole. In this protocol, the synthesis of DPEPhos bcp copper(I)hexafluorophosphate is particularly convenient and can be easily performed on a multigram scale. The proton and carbon-13 NMR spectra indicate formation of the pure complex.The UV and visible light absorption spectrum displays two main absorption bands with two maxima at 385 nanometers and 485 nanometers. The emission spectrum obtained by excitation at 445 nanometers displays maximum at 535 nanometers. As for the characterization of the C2 arylated pyrrole, the proton and carbon-13 NMR spectra indicate formation of the pure compound.The photocatalyst can be used for the synthesis of other molecules as exemplified with the total synthesis of the anti-cancer agent, luotonin A, which demonstrated a good purity shown by its proton and carbon-13 NMR spectra. One of the most important things to remember is that molecular oxygen can be activated by the photocatalyst and induce side reaction. As a consequence, all reactions should therefore be performed under argon and with strict exclusion of oxygen.Copper-based photoredox catalyst can be utilized in other areas of photocatalysis and other copper complexes are being developed and studied right now. The photoreactor emits strong light and care should therefore be taken to turn it on only after closing the door. And to avoid any further exposure, UV-filtering goggles should be worn in addition.

dpephosbcpcupf6-general-broadly-applicable-copper-based-photoredox

Research

JoVE Journal

Chemistry

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

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of molecular iodine to samarium metal in THF.1,2-3 It is a mild and selective single electron reductant and its versatility is a result of its ability to initiate a wide range of reductions including C-C bond-forming and cascade or sequential reactions. SmI2 can reduce a variety of functional groups including sulfoxides and sulfones, phosphine oxides, epoxides, alkyl and aryl halides, carbonyls, and conjugated double bonds.2-12 One of the fascinating features of SmI-2-mediated reactions is the ability to manipulate the outcome of reactions through the selective use of cosolvents or additives. In most instances, additives are essential in controlling the rate of reduction and the chemo- or stereoselectivity of reactions.13-14 Additives commonly utilized to fine tune the reactivity of SmI2 can be classified into three major groups: (1) Lewis bases (HMPA, other electron-donor ligands, chelating ethers, etc.), (2) proton sources (alcohols, water etc.), and (3) inorganic additives (Ni(acac)2, FeCl3, etc).3
Understanding the mechanism of SmI2 reactions and the role of the additives enables utilization of the full potential of the reagent in organic synthesis. The Sm-Barbier reaction is chosen to illustrate the synthetic importance and mechanistic role of two common additives: HMPA and Ni(II) in this reaction. The Sm-Barbier reaction is similar to the traditional Grignard reaction with the only difference being that the alkyl halide, carbonyl, and Sm reductant are mixed simultaneously in one pot.1,15 Examples of Sm-mediated Barbier reactions with a range of coupling partners have been reported,1,3,7,10,12 and have been utilized in key steps of the synthesis of large natural products.16,17 Previous studies on the effect of additives on SmI2 reactions have shown that HMPA enhances the reduction potential of SmI2 by coordinating to the samarium metal center, producing a more powerful,13-14,18 sterically encumbered reductant19-21 and in some cases playing an integral role in post electron-transfer steps facilitating subsequent bond-forming events.22 In the Sm-Barbier reaction, HMPA has been shown to additionally activate the alkyl halide by forming a complex in a pre-equilibrium step.23
Ni(II) salts are a catalytic additive used frequently in Sm-mediated transformations.24-27 Though critical for success, the mechanistic role of Ni(II) was not known in these reactions. Recently it has been shown that SmI2 reduces Ni(II) to Ni(0), and the reaction is then carried out through organometallic Ni(0) chemistry.28
These mechanistic studies highlight that although the same Barbier product is obtained, the use of different additives in the SmI2 reaction drastically alters the mechanistic pathway of the reaction. The protocol for running these SmI2-initiated reactions is described.

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

A straightforward procedure for the preparation of samarium diiodide (SmI2) in THF is described. The role of two main additives namely hexamethylphosphoramide (HMPA) and Ni(acac)2 in Sm mediated reactions is demonstrated in the Sm-Barbier reaction.

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

Quantitative Proteomics Using Reductive Dimethylation for Stable Isotope Labeling

Stable isotope labeling of peptides by reductive dimethylation (ReDi labeling) is a method to accurately quantify protein expression differences between samples using mass spectrometry. ReDi labeling is performed using either regular (light) or deuterated (heavy) forms of formaldehyde and sodium cyanoborohydride to add two methyl groups to each free amine. Here we demonstrate a robust protocol for ReDi labeling and quantitative comparison of complex protein mixtures. Protein samples for comparison are digested into peptides, labeled to carry either light or heavy methyl tags, mixed, and co-analyzed by LC-MS/MS. Relative protein abundances are quantified by comparing the ion chromatogram peak areas of heavy and light labeled versions of the constituent peptide extracted from the full MS spectra. The method described here includes sample preparation by reversed-phase solid phase extraction, on-column ReDi labeling of peptides, peptide fractionation by basic pH reversed-phase (BPRP) chromatography, and StageTip peptide purification. We discuss advantages and limitations of ReDi labeling with respect to other methods for stable isotope incorporation. We highlight novel applications using ReDi labeling as a fast, inexpensive, and accurate method to compare protein abundances in nearly any type of sample.

Stable isotope labeling of peptides by reductive dimethylation (ReDi labeling) is a rapid, inexpensive strategy for accurate mass spectrometry-based quantitative proteomics. Here we demonstrate a robust method for preparation and analysis of protein mixtures using the ReDi approach that can be applied to nearly any sample type.

Stable isotope labeling of peptides by reductive dimethylation (ReDi labeling) is a method to accurately quantify protein expression differences between ...

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and engineers. Growth of such anisotropic nanocrystals through a simple chemical method is a challenging task. In this study, we fabricate discotic nanodisks of zirconium phosphate [Zr(HPO4)2&#183;H2O] as a model material using hydrothermal, reflux and microwave-assisted methods. Growth of crystals is controlled by duration time, temperature, and concentration of reacting species. The novelty of the adopted methods is that discotic crystals of size ranging from hundred nanometers to few micrometers can be obtained while keeping the polydispersity well within control. The layered discotic crystals are converted to monolayers by exfoliation with tetra-(n)-butyl ammonium hydroxide [(C4H9)4NOH, TBAOH]. Exfoliated disks show isotropic and nematic liquid crystal phases. Size and polydispersity of disk suspensions is highly important in deciding their phase behavior.

A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers.

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and ...

HKUST-1 as a Heterogeneous Catalyst for the Synthesis of Vanillin

Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. The natural vanilla scent is a mixture of approximately 200 different odorant compounds in addition to vanillin. The natural extraction of vanillin (from the orchid Vanilla planifolia, Vanilla tahitiensis and Vanilla pompon) represents only 1% of the worldwide production and since this process is expensive and very long, the rest of the production of vanillin is synthesized. Many biotechnological approaches can be used for the synthesis of vanillin from lignin, phenolic stilbenes, isoeugenol, eugenol, guaicol, etc., with the disadvantage of harming the environment since these processes use strong oxidizing agents and toxic solvents. Thus, eco-friendly alternatives on the production of vanillin are very desirable and thus, under current investigation. Porous coordination polymers (PCPs) are a new class of highly crystalline materials that recently have been used for catalysis. HKUST-1 (Cu3(BTC)2(H2O)3, BTC = 1,3,5-benzene-tricarboxylate) is a very well known PCP which has been extensively studied as a heterogeneous catalyst. Here, we report a synthetic strategy for the production of vanillin by the oxidation of trans-ferulic acid using HKUST-1 as a catalyst.

The conversion of trans-ferulic acid to vanillin was achieved by heterogeneous catalysis. HKUST-1 was employed in this synthesis and the essential step in the catalytic process was the generation of unsaturated metal sites. Thus, when the catalyst was activated under vacuum, full vanillin conversion (yield of 95%) was obtained.

Vanillin (4-hydoxy-3-methoxybenzaldehyde) is the main component of the extract of vanilla bean. The natural vanilla scent is a mixture of approximately ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

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

Peptide and Protein Quantification Using Automated Immuno-MALDI (iMALDI)

Mass spectrometry (MS) is one of the most commonly used technologies for quantifying proteins in complex samples, with excellent assay specificity as a result of the direct detection of the mass-to-charge ratio of each target molecule. However, MS-based proteomics, like most other analytical techniques, has a bias towards measuring high-abundance analytes, so it is challenging to achieve detection limits of low ng/mL or pg/mL in complex samples, and this is the concentration range for many disease-relevant proteins in biofluids such as human plasma. To assist in the detection of low-abundance analytes, immuno-enrichment has been integrated into the assay to concentrate and purify the analyte before MS measurement, significantly improving assay sensitivity. In this work, the immuno- Matrix-Assisted Laser Desorption/Ionization (iMALDI) technology is presented for the quantification of proteins and peptides in biofluids, based on immuno-enrichment on beads, followed by MALDI-MS measurement without prior elution. The anti-peptide antibodies are functionalized on magnetic beads, and incubated with samples. After washing, the beads are directly transferred onto a MALDI target plate, and the signals are measured by a MALDI-Time of Flight (MALDI-TOF) instrument after the matrix solution has been applied to the beads. The sample preparation procedure is simplified compared to other immuno-MS assays, and the MALDI measurement is fast. The whole sample preparation is automated with a liquid handling system, with improved assay reproducibility and higher throughput. In this article, the iMALDI assay is used for determining the peptide angiotensin I (Ang I) concentration in plasma, which is used clinically as readout of plasma renin activity for the screening of primary aldosteronism (PA).

Peptide and Protein Quantification Using Automated Immuno-MALDI iMALDI

A protocol for the protein quantification in complex biological fluids using automated immuno-MALDI (iMALDI) technology is presented.

Mass spectrometry (MS) is one of the most commonly used technologies for quantifying proteins in complex samples, with excellent assay specificity as a ...

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Here, we describe an effective protocol that combines photoredox Ni/Ir catalysis with the use of a Zn-alkoxide for efficient ring-opening polymerization, allowing for the synthesis of isotactic poly(&#945;-hydroxy acids) with expected molecular weights (&#62;140 kDa) and narrow molecular weight distributions (Mw/Mn &#60; 1.1). This ring-opening polymerization is mediated by Ni and Zn complexes in the presence of an alcohol initiator and a photoredox Ir catalyst, irradiated by a blue LED (400 - 500 nm). The polymerization is performed at a low temperature (-15 &#176;C) to avoid undesired side reactions. The complete monomer consumption can be achieved within 4 - 8 hours, providing a polymer close to the expected molecular weight with narrow molecular weight distribution. The resulted number-average molecular weight shows a linear correlation with the degree of polymerization up to 1000. The homodecoupling 1H NMR study confirms that the obtained polymer is isotactic without epimerization. This polymerization reported herein offers a strategy for achieving rapid, controlled O-carboxyanhydrides polymerization to prepare stereoregular poly(&#945;-hydroxy acids) and its copolymers bearing various functional side-chain groups.

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

A protocol for the controlled photoredox ring-opening polymerization of O-carboxyanhydrides mediated by Ni/Zn complexes is presented.

Here, we describe an effective protocol that combines photoredox Ni/Ir catalysis with the use of a Zn-alkoxide for efficient ring-opening polymerization, ...

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

This protocol presents both the synthesis method of the Ni single atom catalyst, and the electrochemical testing of its catalytic activity and selectivity in aqueous CO2 reduction. Different from traditional metal nanocrystals, the synthesis of metal single atoms involves a matrix material that can confine those single atoms and prevent them from aggregation. We report an electrospinning and thermal annealing method to prepare Ni single atoms dispersed and coordinated in a graphene shell, as active centers for CO2 reduction to CO. During the synthesis, N dopants play a critical role in generating graphene vacancies to trap Ni atoms. Aberration-corrected scanning transmission electron microscopy and three-dimensional atom probe tomography were employed to identify the single Ni atomic sites in graphene vacancies. Detailed setup of electrochemical CO2 reduction apparatus coupled with an on-line gas chromatography is also demonstrated. Compared to metallic Ni, Ni single atom catalyst exhibit dramatically improved CO2 reduction and suppressed H2 evolution side reaction.

Synthesis and Performance Characterizations of Transition Metal Single Atom Catalyst for Electrochemical CO2 Reduction

Here, we present a protocol for the synthesis and electrochemical testing of transition metal single atoms coordinated in graphene vacancies as active centers for selective carbon dioxide reduction to carbon monoxide in aqueous solutions.

This protocol presents both the synthesis method of the Ni single atom catalyst, and the electrochemical testing of its catalytic activity and selectivity ...

Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction

A highly efficient transition metal catalyst removal method is developed. The water-soluble catalyst contains a newly-designed NHC ligand for the catalyst removal via host-guest interactions. The new NHC ligand possesses an adamantyl (guest) tethered linear ethylene glycol units for hydrophobic inclusion into the cavity of a &#946;-cyclodextrin (&#946;-CD) host compound. The new NHC ligand was applied to a Ru-based olefin metathesis catalyst. The Ru catalyst demonstrated excellent activity in representative ring-closing metathesis (RCM) and ring-opening metathesis polymerization (ROMP) reactions in aqueous media as well as organic solvent, CH2Cl2. After the reaction was complete, the lingering Ru residue was removed from the aqueous solution with the efficiency of more than 99% (53 ppm of Ru residue) by simple filtration utilizing a host-guest interaction between insoluble silica-grafted &#946;-CD (host) and the adamantyl moiety (guest) on the catalyst. The new Ru catalyst also demonstrated high removal efficiency via extraction when the reaction is run in organic solvent by partitioning the crude reaction mixture between layers of diethyl ether and water. In this way, the catalyst stays in aqueous layer only. In organic layer, the residual Ru amount was only 0.14 ppm in the RCM reactions of diallyl compounds.

A removable water-soluble N-heterocyclic carbene (NHC) ligand in aqueous media via host-guest interaction has been developed. We demonstrated representative olefin metathesis reactions in water as well as in dichloromethane. Via either host-guest interaction or extraction, the residual ruthenium (Ru) catalyst was as low as 0.14 ppm after the reaction.

A highly efficient transition metal catalyst removal method is developed. The water-soluble catalyst contains a newly-designed NHC ligand for the catalyst ...

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.

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