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  1. Article: Reactivity of Aluminum Clusters with Water and Alcohols: Competition and Catalysis?

    Luo, Zhixun / Smith, Jordan C / Woodward, W Hunter / Castleman, A W

    The journal of physical chemistry letters

    2012  Volume 3, Issue 24, Page(s) 3818–3821

    Abstract: An in-depth investigation is presented on the hydrogen evolution reaction of aluminum clusters with water and methanol/isopropanol. Aluminum clusters were found to undertake an etching effect in the presence of methanol, but also resulted in an addition ... ...

    Abstract An in-depth investigation is presented on the hydrogen evolution reaction of aluminum clusters with water and methanol/isopropanol. Aluminum clusters were found to undertake an etching effect in the presence of methanol, but also resulted in an addition reaction with isopropanol. Such reactivity without producing hydrogen is different than water, although they all contain an OH group. Further, we studied the competition of water versus alcohols reacting with Al clusters by simultaneously introducing them into a fast-flow tube reactor. Water dominates the competitive reaction with Al clusters, and the O-H bond in water is readily activated to form aluminum hydroxide cluster products. Also found is that water functions as a catalyst in the activation of the O-H bond in alcohol molecules.
    Language English
    Publishing date 2012-12-20
    Publishing country United States
    Document type Journal Article
    ISSN 1948-7185
    ISSN 1948-7185
    DOI 10.1021/jz301830v
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: The growth of ionic crystals based on the halogenation of copper cluster anions.

    Luo, Zhixun / Smith, Jordan C / Woodward, W Hunter / Castleman, A W

    The journal of physical chemistry. A

    2012  Volume 116, Issue 9, Page(s) 2012–2017

    Abstract: We investigated the halogenation reactivity of copper cluster anions produced via a magnetron-sputter source after introduction into a fast-flow tube reaction apparatus simultaneously with chlorine gas. Interesting cluster products corresponding to [Cu(n) ...

    Abstract We investigated the halogenation reactivity of copper cluster anions produced via a magnetron-sputter source after introduction into a fast-flow tube reaction apparatus simultaneously with chlorine gas. Interesting cluster products corresponding to [Cu(n)Cl(n+1)](-) (n = 1-6) were observed with notable stability, and the mass distribution of these clusters exhibits an exponential decay with increasing values of n. Reaction kinetics analysis is provided on the gas-phase reactivity of copper cluster anions with chlorine. First-principle calculations suggest a series of cubic-like structures for these species similar to the structure of alkali halide clusters due to their similar electronic configurations. These structures act as a starting point in the formation of ionic crystals.
    Language English
    Publishing date 2012-03-08
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/jp211636r
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Edge-induced active sites enhance the reactivity of large aluminum cluster anions with alcohols.

    Reber, Arthur C / Roach, Patrick J / Woodward, W Hunter / Khanna, Shiv N / Castleman, A W

    The journal of physical chemistry. A

    2012  Volume 116, Issue 30, Page(s) 8085–8091

    Abstract: Understanding the emergence of properties from the size-selective cluster regime to larger nanoparticles is one of the principal goals of nanoscience. We have measured the size-selective reactivity of aluminum cluster anions with alcohols. All clusters ... ...

    Abstract Understanding the emergence of properties from the size-selective cluster regime to larger nanoparticles is one of the principal goals of nanoscience. We have measured the size-selective reactivity of aluminum cluster anions with alcohols. All clusters with more than 20 atoms are found to be reactive, while Al11(-), Al13(-), and Al20(-) show enhanced resistance to oxidation at smaller sizes. The reactivity of aluminum cluster anions with water, methanol, and tert-butyl alcohol all exhibit patterns that require complementary active sites (Lewis acid, Lewis base) on adjacent atoms. Theoretical investigations reveal that at small sizes, the location of reactive pairs occurs on specific active sites, but at larger sizes the reactive pairs begin to accumulate on the edges between facets, marking the transition from the nonscalable size-dependent regime to the scalable regime where the nanoparticles are universally reactive.
    Language English
    Publishing date 2012-08-02
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/jp3047196
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Reactivity of aluminum cluster anions with water: origins of reactivity and mechanisms for H2 release.

    Reber, Arthur C / Khanna, Shiv N / Roach, Patrick J / Woodward, W Hunter / Castleman, A W

    The journal of physical chemistry. A

    2010  Volume 114, Issue 20, Page(s) 6071–6081

    Abstract: The reactivity of aluminum anion clusters with water was found to exhibit variations with size, with some clusters exhibiting negligible reactivity, others absorbing one or more water, while even others releasing H(2) with addition of multiple waters. ( ... ...

    Abstract The reactivity of aluminum anion clusters with water was found to exhibit variations with size, with some clusters exhibiting negligible reactivity, others absorbing one or more water, while even others releasing H(2) with addition of multiple waters. (Roach, P.J., Woodward, W.H. et al. Science, 2009, 323, 492). Herein, we provide further details on the role of complementary active sites in the breaking of the O-H bond on the cluster. We examine the reactions of Al(n)(-) + H(2)O where n = 7-18, and show how the complementary active sites may be best identified. The clusters with active sites are found to be reactive, and clusters with barriers to reactivity have an absence of paired active sites. The role of charge in the reactivity is considered, which could account for the observed increase in reactivity at large sizes. The H(2) release in the reactivity of Al(17)(-) with multiple water molecules is also studied by comparing multiple reaction pathways, and the selective H(2) production is explained by the first water inducing a new active site. A mechanism for transferring hydroxyl groups on the surface of the cluster is also discussed.
    Language English
    Publishing date 2010-05-27
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/jp911136s
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Complementary active sites cause size-selective reactivity of aluminum cluster anions with water.

    Roach, Patrick J / Woodward, W Hunter / Castleman, A W / Reber, Arthur C / Khanna, Shiv N

    Science (New York, N.Y.)

    2009  Volume 323, Issue 5913, Page(s) 492–495

    Abstract: The reactions of metal clusters with small molecules often depend on cluster size. The selectivity of oxygen reactions with aluminum cluster anions can be well described within an electronic shell model; however, not all reactions are subject to the same ...

    Abstract The reactions of metal clusters with small molecules often depend on cluster size. The selectivity of oxygen reactions with aluminum cluster anions can be well described within an electronic shell model; however, not all reactions are subject to the same fundamental constraints. We observed the size selectivity of aluminum cluster anion reactions with water, which can be attributed to the dissociative chemisorption of water at specific surface sites. The reactivity depends on geometric rather than electronic shell structure. Identical arrangements of multiple active sites in Al16-, Al17-, and Al18- result in the production of H2 from water.
    Language English
    Publishing date 2009-01-23
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 128410-1
    ISSN 1095-9203 ; 0036-8075
    ISSN (online) 1095-9203
    ISSN 0036-8075
    DOI 10.1126/science.1165884
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Complementary Active Sites Cause Size-Selective Reactivity of Aluminum Cluster Anions with Water

    Roach, Patrick J / Castleman, A.W. Jr / Khanna, Shiv N / Reber, Arthur C / Woodward, W. Hunter

    Science. 2009 Jan. 23, v. 323, no. 5913

    2009  

    Abstract: The reactions of metal clusters with small molecules often depend on cluster size. The selectivity of oxygen reactions with aluminum cluster anions can be well described within an electronic shell model; however, not all reactions are subject to the same ...

    Abstract The reactions of metal clusters with small molecules often depend on cluster size. The selectivity of oxygen reactions with aluminum cluster anions can be well described within an electronic shell model; however, not all reactions are subject to the same fundamental constraints. We observed the size selectivity of aluminum cluster anion reactions with water, which can be attributed to the dissociative chemisorption of water at specific surface sites. The reactivity depends on geometric rather than electronic shell structure. Identical arrangements of multiple active sites in Al₁₆⁻, Al₁₇⁻, and Al₁₈⁻ result in the production of H₂ from water.
    Keywords active sites ; aluminum ; anions ; geometry ; hydrogen ; models ; oxygen
    Language English
    Dates of publication 2009-0123
    Size p. 492-495.
    Publishing place American Association for the Advancement of Science
    Document type Article
    ZDB-ID 128410-1
    ISSN 1095-9203 ; 0036-8075
    ISSN (online) 1095-9203
    ISSN 0036-8075
    DOI 10.1126/science.1165884
    Database NAL-Catalogue (AGRICOLA)

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    In stock of ZB MED Bonn / Germany

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