Coordination chemistry of metal surfaces - carbon monoxide chemisorption states on platinum(111)

Friend, Cynthia M.; Gavin, R. M.; Muetterties, E. L.; Tsai, M.-C.

doi:10.1021/ja00525a042

Cited by 15 publications

(5 citation statements)

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“…There remains the possibility that the observed benzene desorption temperature on Ni( 11 1) is not representative of the average chemisorbed benzene molecule because either the desorbed benzene molecules represent not the ordered state but a second state, superimposed on the former, wherein only a partial segment of the benzene orbitals have access to the surface metal orbitals, or the desorbed benzene molecules are associated with states that are perturbed by the ubiquitous surface imperfections of a real single crystal. 23 Since the distinctions between the thermal desorption behavior for benzene on Ni[9(111) X ( l l l ) ] and Ni[7(111) X (310)] surfaces were experimentally nondifferentiable from Ni( 11 l), the latter explanation seems untenable. The apparent higher bond energy for benzene bound to the Ni( 100) surface with respect to the Ni( 11 1) surface can be explained by the lower work function and the higher d orbital occupancy of the (100) surface ifbenzene is largely functioning as an acceptor molecule.…”

Section: C~h S C D~ and Formentioning

confidence: 99%

Coordination chemistry of metal surfaces. 3. Benzene and toluene interactions with nickel surfaces

Friend¹,

Muetterties²

1981

J. Am. Chem. Soc.

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118

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Section: C~h S C D~ and Formentioning

confidence: 99%

Coordination chemistry of metal surfaces. 3. Benzene and toluene interactions with nickel surfaces

Friend¹,

Muetterties²

1981

J. Am. Chem. Soc.

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118

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“…The basic ultra-high vacuum system, the experimental protocols, and the source and the cleaning procedure for the platinum (111) crystals have been described in full in earlier papers (2)(3)(4). The cleaning procedure for Pt(100) is that described by Fischer et al (5), and the clean platinum surface generated showed the 5 x 20 low energy electron diffiaction pattern.…”

Section: Methodsmentioning

confidence: 99%

Chemistry of acetylene on platinum (111) and (100) surfaces

Muetterties

Tasi

Kelemen

1981

Proc. Natl. Acad. Sci. U.S.A.

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An ultra-high vacuum experimental study of acetylene chemisorption on Pt(111) and Pt(100) and ofthe reaction of hydrogen with the acetylene adsorbate has established distinguishing features of carbon-hydrogen bond breaking and making processes as a function ofpressure, temperature, and surface crystallography. The rates for both processes are substantially higher on the Pt(100) surface. Net acetylene-hydrogen processes, in the temperature range of 20°C to -13rC, are distinctly different on the two surfaces: on Pt(100) the net reaction is hydrogen exchange ('H. H exchange) and on Pt(III) the only detectable reaction is hydrogenation. Stereochemical differences in the acetylene adsorbate structure are considered to be a contributing factor to the differences in acetylene chemistry on these two surfaces.Essential to an in-depth understanding of hydrocarbon chemistry mediated at metal surfaces is the delineation ofthe surface electronic, topological, and compositional features that significantly affect carbon-hydrogen bond making and breaking processes. Because the activation energy for carbon-hydrogen bond breaking is typically much lower than for carbon-carbon bond breaking, it is, in principle, experimentally easier to study this type ofreaction. Using primarily the techniques ofthermal desorption spectroscopy, displacement reactions, and isotopic labeling under ultra-high vacuum conditions, Friend and Muetterties (1) have successfully defined molecular features of benzene and toluene chemistry on a range ofnickel surface planes. We describe here an analogous study of acetylene chemisorption and acetylene reactions on the flat platinum (111) and (100) planes. This study establishes the temperatures required for carbon-hydrogen bond making and for carbon-hydrogen bond breaking for the acetylene molecule on these platinum surfaces and also sets certain limits for the compositional and stereochemical features of the chemisorbed species derived from acetylene. EXPERIMENTAL Reagents. Acetylene, purchased from Matheson, was passed through a -780C cold trap before admission to the manifold leading to the ultra high vacuum chamber. Perdeuteroacetylene, 99 atom % C22H2, was purchased from Merck; mass spectrometric analysis indicated the C22H2 concentration was -95%. Hydrogen (99.95%) and deuterium (99.7%) were purchased from Matheson (East Rutherford, NJ) and Liquid Carbonic (Chicago), respectively.Procedure. The basic ultra-high vacuum system, the experimental protocols, and the source and the cleaning procedure for the platinum (111) crystals have been described in full in earlier papers (2-4). The cleaning procedure for Pt(100) is that described by Fischer et al (5), and the clean platinum surface generated showed the 5 x 20 low energy electron diffiaction pattern. The 5 X 20 surface converted to the 1 X 1 structure with exposure to acetylene (5). The 1 x 1 surface is stabilized by the presence of acetylene and is present during the hydrogenation and dehydrogenation processes discussed in this article. RESULTS...

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“…Controlled introduction of carbon atoms on the nickel surface was by treatment of the crystal with either benzene or methyl isocyanide at elevated temperatures. Nickel and platinum crystal blanks with the front face (only) covered with a gold microcrystalline layer (-0.0002 inches thick) were prepared by procedures described elsewhere (3,4). Experiments with "real" surfaces at low or ambient pressures included Raney nickel, nickel from hydrogen reduction of nickel oxide, nickel foil and a nickel(lll) surface (with the sides and back covered with gold--only the (111) surface was exposed).…”

Section: Methodsmentioning

confidence: 99%

“…Interestingly, this cluster has not been prepared directly from the nitrile but by an indirect two-step synthesis outlined in equations 2 and 3 below: HFe3(CO)11 + RCN(moist)-HFe3(CO)g(HN=CR) (2) HFe3(CO) g(HN=CR) OXLOI' Fe3(C0) g(NCR) (3) This structurally defined cluster (10) Alkyl isocyanides are relatively strong field ligands in transition metal chemistry; the molecules are both good c donor and it acceptor ligands and typically the isocyanides readily displace carbon monoxide from mononuclear or polynuclear metal carbonyl complexes. Since methyl isocyanide is strongly bound on both the Ni(lll) and Pt(lll) surfaces, the thermochemical features of CH3CN and CH3NC chemisorption on these surfaces are fully analogous to that of molecular coordination compounds.…”

Section: Unauthenticatedmentioning

confidence: 99%

Coordination chemistry of metal surfaces and metal complexes

Muetterties

1980

Pure and Applied Chemistry

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-The coordination chenistry of two isomeric molecules, acetonitrile and nethyl isocyanide, has been characterized for (A) single crystal nickel surfaces as a function of crystallography and surface composition, (B) nickel catalyst surfaces,and (C) molecular mononuclear and polynuclear metal complexes. Conditions have been established for the catalytic isomerization of methyl isocyanide to acetonitrile within these nickel surface and molecular complex regimes. A comparison is made of the acetonitrile and methyl isocyanide chemistry between the surface and molecular complex areas.

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Coordination chemistry of metal surfaces - carbon monoxide chemisorption states on platinum(111)

Cited by 15 publications

References 0 publications

Coordination chemistry of metal surfaces. 3. Benzene and toluene interactions with nickel surfaces

Coordination chemistry of metal surfaces. 3. Benzene and toluene interactions with nickel surfaces

Chemistry of acetylene on platinum (111) and (100) surfaces

Coordination chemistry of metal surfaces and metal complexes

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