Cycloadditions on Diamond (100) 2 × 1:  Observation of Lowered Electron Affinity due to Hydrocarbon Adsorption

Ouyang, Ti; Gao, Xingyu; Qi, Dongchen; Wee, Andrew Thye Shen

doi:10.1021/jp056785i

Cited by 15 publications

(26 citation statements)

References 37 publications

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“…Figure 1 shows core‐level photoemission spectra of the C1s electrons collected at two different electron take‐off angles (using a photon energy of 350 eV) after the sep‐by‐step deposition of C 60 onto a bare diamond (100)‐2×1 surface. Figure 1 a shows that the C1s emission peaks attributed to the bulk and the surface dimer are observed at 284.8 and 283.9 eV, respectively 24. A new peak, attributed to C 60 , appears at 284.1 eV after evaporating 0.2 monolyers of C 60 onto the surface (see Figure 1 b).…”

Section: Resultsmentioning

confidence: 94%

“…What is the electronic structure of such an interface? In a previous study, we investigated the cycloaddition of a series of molecules, such as acetylene, allyl organics, and 1,3‐butadiene,24 on reconstructed diamond C(100)‐2×1. We found that conjugated molecules, such as 1,3‐butadiene, have high sticking probability and thermal stability on diamond 24–26.…”

Section: Introductionmentioning

confidence: 99%

“…In a previous study, we investigated the cycloaddition of a series of molecules, such as acetylene, allyl organics, and 1,3‐butadiene,24 on reconstructed diamond C(100)‐2×1. We found that conjugated molecules, such as 1,3‐butadiene, have high sticking probability and thermal stability on diamond 24–26. On the other hand, C 60 —being a strained, electron‐deficient poly‐alkene with rather localized bonds—can react as both a diene or a dienophile in Diels–Alder reactions 27.…”

Section: Introductionmentioning

confidence: 99%

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Chemical Bonding of Fullerene and Fluorinated Fullerene on Bare and Hydrogenated Diamond

Ouyang

Wee

et al. 2008

ChemPhysChem

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We investigate the interface between a C(60) fullerite film, C(60)F(36), and diamond (100) by using core-level photoemission spectroscopy, cyclic voltammetry (CV), and high-resolution electron energy loss spectroscopy (HREELS). We show that C(60) can be covalently bonded to reconstructed C(100)-2x1 and that the bonded interface is sufficiently robust to exhibit characteristic C(60) redox peaks in solution. The bare diamond surface can be passivated against oxidation and hydrogenation by covalently bound C(60). However, C(60)F(36) is not as stable as C(60) and desorbs below 300 degrees C (the latter species being stable up to 500 degrees C on the diamond surface). Neither C(60) fullerite nor C(60)F(36) form reactive interfaces on the hydrogenated surface-they both desorb below 300 degrees C. The surface transfer doping process of hydrogenated diamond by C(60)F(36) is the most evident one among all the adsorbate systems studied (with a coverage-dependent band bending induced by C(60)F(36)).

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Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chemical Bonding of Fullerene and Fluorinated Fullerene on Bare and Hydrogenated Diamond

Ouyang

Wee

et al. 2008

ChemPhysChem

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“…The surface product was found to be stable up to approximately 1,000 K [59,60]. 1,3-Butadiene attains high coverage as well as forms a thermally stable adlayer on reconstructed diamond (100)-2 × 1 surface due to its ability to undergo [4+2] cycloaddition [61].…”

Section: [4+2] Cycloadditions On Surfacementioning

confidence: 99%

A Mechanistic Spectrum of Chemical Reactions

Inagaki

2009

Orbitals in Chemistry

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The mechanism of chemical reactions between electron donors and acceptors continuously changes with the power of the donors and the acceptors. The interaction between the HOMO (d) of the donors and the LUMO (a*) of the acceptors or delocalization of electrons is important for the reactions. The electron d-to-a* transferred configuration mixes to a significant extent. As the donors and/or the acceptors are strong, their excited configurations appreciably mixes together with the transferred configuration. The d-a and d*-a* orbital interactions are important in addition to the d-a* interaction. Reactions have features characteristic of the excited-state reactions although the donor-acceptor system is not really excited, but in the ground state. This process is termed pseudoexcitation. The a-d-a*-d* interaction is important. For much stronger donors and acceptors, the electron transferred configuration is stable and predominant. Covalent bonds do not form but instead ionic pairs, and electron transfer results. A mechanistic spectrum of chemical reactions is composed of the delocalization, pseudoexcitation, and electron transfer bands.

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“…Indeed, we have previously observed the lowering of electron affinities on CA C H T U N G T R E N N U N G (100) 2 1 following hydrocarbon adsorption. [12,13] Several factors, such as the coverage of these hydrocarbons on diamond, as well as the geometrical orientation of the CÀH dipoles on these adsorbed species, may produce different effects on the surface electronic properties of the diamond. In order to investigate the roles of these factors, we carry out sticking probability studies to assess the reactivity of the clean diamond surface towards allyl organics such as acetylene and butadiene.…”

Section: Introductionmentioning

confidence: 99%

Spatial Effect of CH Dipoles on the Electron Affinity of Diamond (100)‐2×1 Adsorbed with Organic Molecules

Hoh

Sullivan

2008

ChemPhysChem

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Cycloaddition of allyl organics on the dimer rows of a clean C(100)-2x1 diamond surface can be used for the controlled functionalization of such a surface. Sticking probability measurements confirm that appreciable uptake of acetylene and butadiene occur on the clean diamond surface at room temperature. The change in electron affinity of the surface as a function of the coverage of the organic molecules is investigated with periodic DFT calculations. The presence of C-H dipoles on these adsorbates modify the surface charge density and gives rise to an induced dipolar layer that modifies the electrostatic potential outside the surface. There is a significant reduction of up to 2.5 eV in electron affinity following the chemisorption of ethylene. Therefore, the adsorbed molecules play the same role as surface hydrogen in inducing the NEA condition on the clean diamond. The change in electron affinity does not scale linearly with the coverage of the organic molecules, because the spatial profile of the C-H dipoles as well as the orientation of the molecules on the surface have a predominant effect on the surface charge density.

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Cycloadditions on Diamond (100) 2 × 1: Observation of Lowered Electron Affinity due to Hydrocarbon Adsorption

Cited by 15 publications

References 37 publications

Chemical Bonding of Fullerene and Fluorinated Fullerene on Bare and Hydrogenated Diamond

Chemical Bonding of Fullerene and Fluorinated Fullerene on Bare and Hydrogenated Diamond

A Mechanistic Spectrum of Chemical Reactions

Spatial Effect of CH Dipoles on the Electron Affinity of Diamond (100)‐2×1 Adsorbed with Organic Molecules

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