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

Friend, Cynthia M.; Muetterties, E. L.

doi:10.1021/ja00394a008

Cited by 119 publications

(63 citation statements)

References 3 publications

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“…Figure 5 summarises the results of the laser desorption study on a toluene sample deposited on a gold-coated silica wafer. Toluene was chosen as a reference molecule for this case study due to its chemical simplicity and affinity with metal substrates, which allows it to be measured in UHV at room temperature (Friend and Muetterties 1981, Tsai and Muetterties 1982, Rauscher et al 1991, Nakazawa and Somorjai 1993, Wetterer et al 1998, Libuda and Scoles 2000.…”

Section: Measurement Proceduresmentioning

confidence: 99%

CAMAM: A Miniature Laser Ablation Ionisation Mass Spectrometer and Microscope‐Camera System for In Situ Investigation of the Composition and Morphology of Extraterrestrial Materials

Tulej

Riedo

Neuland

et al. 2014

Geostandard Geoanalytic Res

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Performance studies of a microscope‐camera system (MCS) and a laser ablation/ionisation mass spectrometer (LIMS) instrument (referred to here as a laser mass spectrometer or LMS) are presented. These two instruments were designed independently for in situ analysis of solids on planetary surfaces and will be combined to a single miniature instrument suite for in situ chemical and morphological analysis of surface materials on planetary bodies. LMS can perform sensitive chemical (elemental, isotope and molecular) analyses with spatial resolution close to micrometre‐sized grains. It allows for studies with mass resolution (M/ΔM) up to 800 in ablation mode (elemental composition) and up to 1500 in desorption mode (molecular analysis). With an effective dynamic range of at least eight orders of magnitude, sensitive and quantitative measurements can be conducted of almost all elements and isotopes with a concentration larger than a few ppb atoms. Hence, in addition to the major element composition, which is important for the determination of mineralogical constituents of surface materials, trace elements can also be measured to provide information on mineral formation processes. Highly accurate isotope ratio measurements can be used to determine in situ geochronology of sample material and for investigations of various isotope fractionation processes. MCS can conduct optical imagery of mm‐sized objects at several wavelengths with micrometre spatial resolution for the characterisation of morphological surface details and to provide insight into surface mineralogy. Furthermore, MCS can help in the selection of sample surface areas for further mass spectrometric analysis of the chemical composition. Surface auto‐fluorescence measurements and images in polarised light are additional capabilities of the MCS, to identify either fluorescing minerals or organic materials, if present on the analysed surface, for further investigation by LMS. The results obtained by investigations of NIST reference materials, amino acid films and a natural graphite sample embedded in silicate rock are presented to illustrate the performance of the instruments and their potential to deliver chemical information for mineral and organic phases in their geological context.

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Section: Measurement Proceduresmentioning

confidence: 99%

CAMAM: A Miniature Laser Ablation Ionisation Mass Spectrometer and Microscope‐Camera System for In Situ Investigation of the Composition and Morphology of Extraterrestrial Materials

Tulej

Riedo

Neuland

et al. 2014

Geostandard Geoanalytic Res

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“…100 There is also circumstantial evidence that benzyl forms from toluene decomposition on nickel surfaces on the basis of TPD studies employing isotope labeling. [158][159][160] …”

Section: Other Alkylsmentioning

confidence: 99%

Mimicking Aspects of Heterogeneous Catalysis: Generating, Isolating, and Reacting Proposed Surface Intermediates on Single Crystals in Vacuum

1996

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“…Here, too, there may be added stabilization if the C-H bonds bend toward the metal surface (25), § but no experimental data bearing on this stereochemical issue have been reported.…”

Section: Discussionmentioning

confidence: 99%

Metal-hydrogen bridge bonding of hydrocarbons on metal surfaces

Gavin

Reutt

Muetterties

1981

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

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Molecular orbital studies implicate multicenter metal-hydrogen-carbon interactions as contributors to the bonding of chemisorbed hydrocarbons on clean metal surfaces. The most stable geometries appear to be those that achieve the maximum multicenter bonding to the coordinately unsaturated metal atoms in the vicinity of the anchoring metal-carbon interaction. Energy differences between possible surface sites are of the same magnitude as stabilization energies for three-center bonding of hydrogen atoms to the metal surface. Accordingly, secondary interactions of hydrogen with neighboring metal atoms may be significant determining factors in surface structures. The model predictions are compared with known structures and are used to propose a mechanism for hydrocarbon reactions on metal surfaces. These metal-hydrogen-carbon interactions are presumed to be intermediate points or states in C-H bond-breaking processes.A characterization of the bonding interaction between surfaces and adsorbed molecules is important to an understanding of surface chemistry. An analogy (1) between susfaces and molecular metal clusters has been proposed as one model framework within which representations for chemical interactions at surface interfaces can be developed. Fundamental to this approach is the assumption that local interactions, rather than bulk metal properties, are the major directors ofchemical reactions on surfaces. Obvious differences between molecular metal clusters and surfaces are conceded, but these differences also are presumed to influence the chemistry in a local fashion. This local model is amenable to theoretical analysis, and numerous attempts have been made to mimic the surface-adsorbate interaction by using semiempirical molecular orbital calculations (2-5). Because of the necessity to deal with finite numbers of orbitals in these methods, computations can be envisaged as theoretical models using a metal cluster for surface approximation. No model successfully predicts all properties of a surface that has chemisorbed species, but several models have had some success in qualitative predictions. In this paper, we describe a model based on the extended Huckel approach (6) in which trends in bond orders and energies are used to predict geometries of adsorbed species on metal surfaces. COMPUTATIONAL PROCEDURE Model surface computations were effected for a close-packed planar array of Ni atoms mimicking the (111) surface plane [for brevity, this pseudosurface will be referred to as Ni(111) throughout this article]. The metal-metal atom distance was taken to be 2.48 A, and the number of Ni atoms used to represent the surface was varied from 6 to 13. Due to the qualitative nature ofthe computations, the trends observed with the sevenatom clusters, close packed in a plane, could not be differentiated from the trends observed for larger clusters in two or more planes. The analysis was limited to the energy and bond order properties of the systems as a function of site and orientation. Bond distances and angles ...

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

Cited by 119 publications

References 3 publications

CAMAM: A Miniature Laser Ablation Ionisation Mass Spectrometer and Microscope‐Camera System for In Situ Investigation of the Composition and Morphology of Extraterrestrial Materials

CAMAM: A Miniature Laser Ablation Ionisation Mass Spectrometer and Microscope‐Camera System for In Situ Investigation of the Composition and Morphology of Extraterrestrial Materials

Mimicking Aspects of Heterogeneous Catalysis: Generating, Isolating, and Reacting Proposed Surface Intermediates on Single Crystals in Vacuum

Metal-hydrogen bridge bonding of hydrocarbons on metal surfaces

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