Observation of ligand effects during alkene hydrogenation catalysed by supported metal clusters


Homogeneous organometallic catalysts and many enzymes activate reactants through coordination to metal atoms; that is, the reactants are turned into ligands and their reactivity controlled through other ligands in the metal's coordination sphere1. In the case of supported metal clusters, catalytic performance is influenced by the support and by adsorbed reactants, intermediates or products. The adsorbates are usually treated as ligands, whereas the influence of the supports is usually ascribed to electronic interactions2,3, even though metal clusters supported on oxides4,5,6 and zeolites7 form chemical bonds to support oxygen atoms. Here we report direct observations of the structure of supported metal clusters consisting of four iridium atoms, and the identification of hydrocarbon ligands bound to them during propene hydrogenation. We find that propene and molecular hydrogen form propylidyne and hydride ligands, respectively8, whereas simultaneous exposure of the reactants to the supported iridium cluster yields ligands that are reactive intermediates during the catalytic propane-formation reaction. These intermediates weaken the bonding within the tetrahedral iridium cluster and the interactions between the cluster and the support, while replacement of the MgO support with γ-Al2O3 boosts the catalytic activity tenfold, by affecting the bonding between the reactant-derived ligands and the cluster and therefore also the abundance of individual ligands. This interplay between the support and the reactant-derived ligands, whereby each influences the interaction of the metal cluster with the other, shows that the catalytic properties of supported metal catalysts can be tuned by careful choice of their supports.

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Figure 1: Infrared spectra of adsorbate ligands on Ir4/γ-Al2O3 during ethene hydrogenation.
Figure 2: Catalytic activity and average ethyl band intensity as a function of p H 2 during ethene hydrogenation catalysed by Ir4/γ-Al2O3.
Figure 3: Schematic representation of the hydrogenation of propene on MgO-supported Ir4.


  1. 1

    Collman, J. P., Hegedus, L. S., Norton, J. R. & Finke, R. G. Principles and Applications of Organotransition Metal Chemistry 2nd edn (University Science Books, Mill Valley, California, 1987).

    Google Scholar 

  2. 2

    Stevenson, S. A., Dumesic, J. A., Baker, R. T. K. & Ruckenstein, E. (eds) Metal-Support Interactions in Catalysis, Sintering, and Redispersion (van Nostrand Reinhold, New York, 1987).

    Google Scholar 

  3. 3

    Haller, G. L. & Resasco, D. E. Metal-support interaction: group VIII metals and reducible oxides. Adv. Catal. 36, 173–235 (1989).

    CAS  Google Scholar 

  4. 4

    Yudanov, I. V., Vent, S., Neyman, K., Pacchioni, G. & Rösch, N. Adsorption of Pd atoms and Pd-4 clusters on the MgO(001) surface: a density functional study. Chem. Phys. Lett. 275, 245–252 (1997).

    ADS  CAS  Article  Google Scholar 

  5. 5

    Matveev, A. V., Neyman, K., Pacchioni, G. & Rösch, N. Density functional study of M-4 clusters (M = Cu, Ag, Ni, Pd) deposited on the regular MgO(001) surface. Chem. Phys. Lett. 299, 603–612 (1999).

    ADS  CAS  Article  Google Scholar 

  6. 6

    Goellner, J. V. et al. Ligand-free osmium clusters supported on MgO: a density functional study. Langmuir 16, 2736–2743 (2000).

    CAS  Article  Google Scholar 

  7. 7

    Ferrari, A. M. et al. Faujasite-supported Ir4 clusters: A density functional model study of metal–zeolite interactions. J. Phys. Chem. B. 103, 5311–5319 (1999).

    CAS  Article  Google Scholar 

  8. 8

    Argo, A. M., Goellner, J. F., Phillips, B. L., Panjabi, G. A. & Gates, B. C. Reactivity of site-isolated metal clusters: propylidyne on γ-Al2O3-supported Ir4. J. Am. Chem. Soc. 123, 2275–2283 (2001).

    CAS  Article  Google Scholar 

  9. 9

    McVicker, G. B. et al. Effect of sulfur on the performance and on the particle size and location of platinum in Pt/KL hexane aromatization catalyst. J. Catal. 139, 48–61 (1993).

    CAS  Article  Google Scholar 

  10. 10

    Jentoft, R. E., Tsapatsis, M., Davis, M. E. & Gates, B. C. Platinum clusters supported in zeolite LTL: influence of catalyst morphology on performance in n-hexane reforming. J. Catal. 179, 565–580 (1998).

    CAS  Article  Google Scholar 

  11. 11

    Xu, Z. et al. Size-dependent catalytic activity of supported metal clusters. Nature 372, 346–348 (1994).

    ADS  CAS  Article  Google Scholar 

  12. 12

    Gates, B. C. Supported metal clusters: synthesis, structure, and catalysis. Chem. Rev. 95, 511–522 (1995).

    CAS  Article  Google Scholar 

  13. 13

    Argo, A. M. Influence of Supports, Cluster Structure, and Cluster Composition on Hydrogenation Reactions Catalyzed by Oxide-Supported Metal Clusters. Thesis, Univ. California at Davis (2001).

    Google Scholar 

  14. 14

    Odzak, J. F., Argo, A. M., Lai, F. S. & Gates, B. C. A flow through X-ray absorption spectroscopy cell for characterization of powder catalysts in the working state. Rev. Sci. Instrum. 72, 3943–3945 (2001).

    ADS  CAS  Article  Google Scholar 

  15. 15

    Cremer, P. S., Su, X., Shen, Y. R. & Somorjai, G. A. Hydrogenation and dehydrogenation of propylene on Pt(111) studied by sum frequency generation from UHV to atmospheric pressure. J. Phys. Chem. 100, 16302–16309 (1996).

    CAS  Article  Google Scholar 

  16. 16

    Cremer, P. S., Su, X., Shen, Y. R. & Somorjai, G. A. Ethylene hydrogenation on Pt(111) monitored in situ at high pressure using sum frequency generation. J. Am. Chem. Soc. 118, 2942–2949 (1996).

    CAS  Article  Google Scholar 

  17. 17

    Shahid, G. & Sheppard, N. Infrared spectra and the structures of the chemisorbed species resulting from the adsorption of propene and propane on a Pt/SiO2 catalyst. Spectrochim. Acta. A 46, 999–1010 (1990).

    ADS  Article  Google Scholar 

  18. 18

    Newell, H. E., McCoustra, M. R. S., Chesters, M. A. & De La Cruz, C. The thermal chemistry of adsorbed ethyl on the Pt(111) surface: infrared evidence for an ethylidene intermediate in the ethyl to ethylidyne conversion. J. Chem. Soc. Faraday Trans. 94, 3695–3698 (1998).

    CAS  Article  Google Scholar 

  19. 19

    Bent, B. E., Mate, C. M., Crowell, J. E., Koel, B. E. & Somorjai, G. A. Bonding and thermal decomposition of propylene, propadiene, and methylacetylene on the Rh(111) single crystal surface. J. Phys. Chem. 91, 1493–1502 (1987).

    CAS  Article  Google Scholar 

  20. 20

    Chesters, M. A. et al. Infrared spectroscopic comparison of the chemisorbed species from ethene, propene, but-1-ene and cis- and trans-but-2-ene on Pt(111) and on a platinum/silica catalyst. J. Chem. Soc. Faraday Trans. 86, 2757–2763 (1990).

    Article  Google Scholar 

  21. 21

    Neurock, M. & van Santen, R. A. A first principles analysis of C–H bond formation in ethylene hydrogenation. J. Phys. Chem. B 104, 11127–11145 (2000).

    CAS  Article  Google Scholar 

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We thank the US National Science Foundation for support and the National Synchrotron Light Source at Brookhaven National Laboratory for beam time.

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Correspondence to B. C. Gates.

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Argo, A., Odzak, J., Lai, F. et al. Observation of ligand effects during alkene hydrogenation catalysed by supported metal clusters. Nature 415, 623–626 (2002). https://doi.org/10.1038/415623a

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