title: New routes to Cu(I)/Cu nanocatalysts for the multicomponent click synthesis of 1,2,3-triazoles.
abstract: An array of copper and copper-zinc based nanoparticles (NPs) have been fabricated employing a variety of polymeric capping agents. Analysis by TEM, XRPD and XPS suggests that by manipulating reagent, reductant and solvent conditions it is possible to achieve materials that are mono-/narrow disperse with mean particle sizes in the ≤10 nm regime. Oxidative stability in air is achieved for monometallic NPs using poly(methyl methacrylate) (PMMA) anti-agglomerant in conjunction with a variety of reducing conditions. In contrast, those encapsulated by either poly(1-vinylpyrrolidin-2-one) (PVP) or poly(4-vinylpyridine) (PVPy) rapidly show Cu(2)O formation, with all data suggesting progressive oxidation from Cu to Cu@Cu(2)O core-shell structure and finally Cu(2)O. Bimetallic copper-zinc systems, reveal metal segregation and the formation of Cu(2)O and ZnO. Catalysts have been screened in the synthesis of 1,2,3-triazoles through multicomponent azide-alkyne 1,3-dipolar cycloaddition. Whereas PMMA- and PVPy-coating results in reduced catalytic activity, those protected by PVP are highly active, with quantitative triazole syntheses achieved at room temperature and with catalyst loadings of 0.03 mol% metal for Cu and CuZn systems prepared using NaH(2)PO(2), N(2)H(4) or NaBH(4) reductants.
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
authors.forename: Pavel
authors.initials: P
authors.lastname: Abdulkin
authors.forename: Yanina
authors.initials: Y
authors.lastname: Moglie
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Knappett
authors.forename: David A
authors.initials: DA
authors.lastname: Jefferson
authors.forename: Miguel
authors.initials: M
authors.lastname: Yus
authors.forename: Francisco
authors.initials: F
authors.lastname: Alonso
authors.forename: Andrew E H
authors.initials: AE
authors.lastname: Wheatley
mesh_terms: D002384:Catalysis; D057930:Click Chemistry / Q000379:methods*; D003300:Copper / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D008968:Molecular Conformation; D010316:Particle Size; D013499:Surface Properties; D014230:Triazoles / Q000737:chemistry*
chemical_list: D046911:Macromolecular Substances; D014230:Triazoles; D003300:Copper