Thiophene adsorption on Pd(111) and Pd(100) surfaces studied by total-reflection S K-edge X-ray absorption fine-structure spectroscopy

Terada, Shin; Yokoyama, Toshihiko; Sakano, M.; Imanishi, Akihito; Kitajima, Yoshinori; Kiguchi, Manabu; Okamoto, Yoshiki; Ohta, Toshiaki

doi:10.1016/s0039-6028(98)00495-6

Cited by 31 publications

(22 citation statements)

References 34 publications

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“…58 The initially proposed adsorption models had the carbons bound essentially η 4 -atop one Pd center with unusually long Pd–C bonds (>2.5 Å c.f. ~2.16 Å in Pd(COD) 2 59 ).…”

Section: Resultsmentioning

confidence: 99%

Dipalladium(I) Terphenyl Diphosphine Complexes as Models for Two-Site Adsorption and Activation of Organic Molecules

et al. 2013

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Well-defined models for binding of organic molecules across two metal centers are relatively rare. A paraterphenyl diphosphine was employed to support a dipalladium(I) moiety. Unlike previously reported dipalladium(I) species, the present system provides a single molecular hemisphere for binding of ligands across two metal centers, enabling the characterization and comparison of the binding of a wide variety of saturated and unsaturated organic molecules. The dipalladium(I) terphenyl diphosphine toluene-capped complex was synthesized from a dipalladium(I) hexaacetonitrile precursor in the presence of toluene. The palladium centers display interactions with the π-systems of the central ring of the terphenyl unit and that of the toluene. Exchange of toluene for anisole, 1,3-butadiene, 1,3-cyclohexadiene, thiophenes, pyrroles, or furans resulted in well-defined π-bound complexes which were studied by crystallography, nuclear magnetic resonance (NMR) spectroscopy, and density functional theory. Structural characterization shows that the interactions of the dipalladium unit with the central arene of the diphosphine does not vary significantly in this series allowing for a systematic comparison of the binding of the incoming ligands to the dipalladium moiety. Several of the complexes exhibit rare μ2-η2:η2 or μ2-η2:η1 (O or S) bridging motifs. Hydrogenation of the thiophene and benzothiophene adducts was demonstrated to proceed at room temperature. The relative binding strength of the neutral ligands was determined by competition experiments monitored by NMR spectroscopy. The relative equilibrium constants for ligand substitution span over 13 orders of magnitude. This represents the most comprehensive analysis to date of the relative binding of heterocycles and unsaturated ligands to bimetallic sites. Binding interactions were computationally studied with electrostatic potentials and molecular orbital analysis. Anionic ligands were also demonstrated to form π-bound complexes.

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“…58 The initially proposed adsorption models had the carbons bound essentially η 4 -atop one Pd center with unusually long Pd–C bonds (>2.5 Å c.f. ~2.16 Å in Pd(COD) 2 59 ).…”

Section: Resultsmentioning

confidence: 99%

Dipalladium(I) Terphenyl Diphosphine Complexes as Models for Two-Site Adsorption and Activation of Organic Molecules

et al. 2013

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“…This has led to an interest in the fundamental interactions of thiophene with metal surfaces, and largely as a result the literature contains surface science studies of thiophene on several different catalytically active metals: Fe͑100͒, 4 Ni͑100͒, 5,6 Cu͑100͒, 5,7 Cu͑111͒, 8,9 Mo͑110͒, 10,11 Ru͑0001͒, 12 Rh͑111͒, 13 Pd͑111͒, 14 Pd͑100͒, 14 Ag͑111͒, 15 Pt͑111͒, 16 and Pt͑100͒. 16 In most cases reasonably strong bonds to the surface were indicated, as thiophene was found not to desorb molecularly from the surface, but rather break up upon heating.…”

Section: Introductionmentioning

confidence: 99%

An experimental and theoretical investigation of the thiophene/aluminum interface

Blyth

Mittendorfer

Häfner

et al. 2001

The Journal of Chemical Physics

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The adsorption of thiophene and 2, 2′-bithiophene on Al(111) has been studied using thermal desorption spectroscopy (TDS), angle-resolved UV photoemission (ARUPS), and work function measurements. Ab initio density functional theory calculations have been performed for thiophene on Al(111). Both thiophene and bithiophene bond only very weakly to Al(111), as indicated by TDS and calculations of the thiophene absorption energy, which is found to be only 0.54 eV. There is no indication of π-bonding in either the ARUPS data or the calculations. The calculated S–Al distance, 3.7 Å, is much greater than either measured or calculated S–metal distances for covalent bonding. The bonding is shown to be almost entirely electrostatic, with a small contribution from the sulfur lone pair. This is in direct contrast to calculations for Al–thiophene complexes which show covalent bonds between the Al atoms and the thiophene α carbons. The calculations show the molecule to be essentially flat, with a tilt angle of only 2° of the molecular plane relative to the surface. There is some indication of self-assembly of bithiophene on Al(111).

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“…To identify a chemisorbed adsorbate on each substrate surfaces, the assignation of NEXAFS peak positions is necessary. From the results of previous studies, we have judged the peak positions of L-cysteine thiolate and atomic S [2,8,12,13]. The spectra for L-cysteine aqueous solution and the NiAl(111) substrate without dipping into L-cysteine aqueous solution under dry environment are also shown as standard and background.…”

Section: A Afm Observationmentioning

confidence: 99%

Adsorption Reaction of Amino Acid Molecule on Pd Thin Layer Surface Constructed by Nano-dots under Water Environment

Tsukada

Ogawa

Niwa

et al. 2011

e-J. Surf. Sci. Nanotechnol.

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The adsorption reaction of L-cysteine on Pd thin layer surface constructed by nano-dots under water environment has been investigated by S K-edge NEXAFS with He-path system under atmospheric pressure. It is revealed that L-cysteine physisorbs on Pd/Al2O3/NiAl(111) substrate surface through the thiol group and the carboxyl one, and chemisorbed L-cysteine exists on the surface as L-cysteine thiolate. Before and after dipping the Pd/Al2O3/NiAl(111) substrate into L-cysteine aqueous solution, the surface morphology is observed using AFM. The morphology of the Pd/Al2O3/NiAl(111) substrate is composed of many nano-dots before dipping. After dipping, the nano-dots are enlarged.

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Thiophene adsorption on Pd(111) and Pd(100) surfaces studied by total-reflection S K-edge X-ray absorption fine-structure spectroscopy

Cited by 31 publications

References 34 publications

Dipalladium(I) Terphenyl Diphosphine Complexes as Models for Two-Site Adsorption and Activation of Organic Molecules

Dipalladium(I) Terphenyl Diphosphine Complexes as Models for Two-Site Adsorption and Activation of Organic Molecules

An experimental and theoretical investigation of the thiophene/aluminum interface

Adsorption Reaction of Amino Acid Molecule on Pd Thin Layer Surface Constructed by Nano-dots under Water Environment

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