title: Synthesis and characterization of nickel nanoparticles dispersed in imidazolium ionic liquids.
abstract: The diameter and size-distribution of Ni nanoparticles prepared by the decomposition of [bis(1,5-cyclooctadiene)nickel(0)] organometallic precursor dissolved in 1-alkyl-3-methylimidazolium N-bis(trifluoromethanesulfonyl) amide ionic liquids depend on the length of the alkyl side-chain of the imidazolium ring. The increase of the organization range order of the ionic liquid that increases with that of the alkyl side-chain (from n-butyl to n-hexadecyl) induces the formation of nanoparticles with a smaller diameter and size-distribution. The cubic fcc Ni nanoparticles with 4.9 +/- 0.9 to 5.9 +/- 1.4 nm in mean diameter and monomodal size-distribution thus prepared are probably composed of a small cap layer of NiO around a core of Ni metal. The contribution of the oxide layer also depends on the medium i.e. the metal oxide ratio increases in salts containing four to eight carbons on their side-chains and then decreases as the number of carbons increases. The Ni nanoparticles dispersed in the ionic liquids are active catalysts for the hydrogenation of olefins under relatively mild reaction conditions.
authors: Laboratory of Molecular Catalysis, Instituto de Química-UFRGS, P.O. Box 15003, Porto Alegre, 91501-970, RS Brazil.
authors: Pedro
authors: P
authors: Migowski
authors: Giovanna
authors: G
authors: Machado
authors: Sergio R
authors: SR
authors: Texeira
authors: Maria C M
authors: MC
authors: Alves
authors: Jonder
authors: J
authors: Morais
authors: Agnès
authors: A
authors: Traverse
authors: Jairton
authors: J
authors: Dupont
mesh_terms: D003102:Colloids / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D048288:Imidazolines / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D009532:Nickel / Q000737:chemistry*; D010316:Particle Size
chemical_list: D003102:Colloids; D048288:Imidazolines; D052578:Ionic Liquids; D009532:Nickel