C−F Bond Cleavage by Mass-Selected Free Radicals at Fluorinated Self-Assembled Monolayer Surfaces

Shen, Jie; Grill, V.; Cooks, R. Graham

doi:10.1021/ja9740531

Cited by 13 publications

(29 citation statements)

References 34 publications

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“…Figure 4 presents the scattered ion mass spectrum recorded upon collision of 187 Re with the fluorocarbon SAM. Many features are similar to the W Á data, but the fluorocarbon abstraction products, ReCF Á , ReCF 2 and ReCF 3 Á are now of comparable abundance to the fluorine abstraction products. It is apparent that high collision energy favors Re-C bond formation over Re-F formation.…”

Section: Resultssupporting

confidence: 56%

“…The reaction thermochemical data for the formation of CrF x (x = 1-3) have been estimated 27 and are displayed in Table 1. As one can see, the formation of CrF 3 is highly endothermic, and this result emphasizes the control of thermochemistry over ion/surface reactions. Figure 2 shows the scattered ion mass spectra recorded upon collision of 98 Mo Á at the fluorocarbon SAM at 90 eV collision energy, as well as an energy resolved mass spectrum (ERMS) plot for collision energies ranging from 20 to 190eV.…”

Section: Resultsmentioning

confidence: 92%

“…This is in accordance with thermochemical considerations, since this reaction is more endothermic than single fluorine abstraction. However, even after increasing the collision energy beyond 100 eV, no CrF 3 is observed. The reaction thermochemical data for the formation of CrF x (x = 1-3) have been estimated 27 and are displayed in Table 1.…”

Section: Resultsmentioning

confidence: 96%

“…Typical Xe Á chemical sputtering spectra of fluorocarbon SAMs show an intensity of CF n peaks in the order CF 3 b CF b CF 2 . However, ReCF 2 and ReCF 3 are roughly of the same intensity above 50 eV.…”

Section: Resultsmentioning

confidence: 99%

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C-F and C-C bond activation by transition metals in low energy atomic ion/surface collisions

Evans

Pradeep

Shen

et al. 1999

Rapid Commun. Mass Spectrom.

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The transition metal ions, Cr Á , MoÁ , W Á and Re , abstract one or more fluorine atoms or C m F n groups (m = 1,2; n = 1-5) in collisions with fluorocarbon self-assembled monolayers (F-SAMs). The number of atoms abstracted increases with collision energy, and with W Á and Re it is possible to maximize a specific scattered product ion by selecting the appropriate collision energy. The collision energy dependence suggests that dissociation of the products of multiple abstractions is not an important source of any of the observed ion/surface reaction products. The ions W Á and Re activate and insert into C-C as well as C-F bonds. In Re collisions, products of C-C bond activation are of comparable intensity to the C-F activation products. The reactivity of the ions towards fluorine abstraction is observed to be Cr. The data are interpreted in terms of reaction at the surface and are rationalized by considering three factors (i) the electronic structures of the ions, (ii) the thermochemistry of fluorine abstraction, and (iii) the degree of orbital overlap of the metal ion and the F-SAM substrate.

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Section: Resultssupporting

confidence: 56%

Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

C-F and C-C bond activation by transition metals in low energy atomic ion/surface collisions

Evans

Pradeep

Shen

et al. 1999

Rapid Commun. Mass Spectrom.

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“…The use of energetic free radicals to e †ect CÈF bond cleavage in Ñuorocarbons in surface reactions has also been reported. 38 This paper focuses on the reactions of silyl cations with Ñuorocarbon surfaces, the associated phenomenon of multiple CÈF bond cleavage and the potential of using the gas-phase polyatomic ions (n \ 3, Si(NCO) n4 ) and as chemical reagents to modify Ñu-ClC(CN) 2ò rocarbon surfaces selectively. Halogen-or pseudohalogen transfer reactions are exploited to introduce functional groups into the F-SAM surfaces.…”

mentioning

confidence: 99%

Chemical modification of fluorinated self-assembled monolayer surfaces using low-energy ion beams for halogen and pseudohalogen transfer

et al. 1999

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C–F and C–C bond activation by transition metals in low energy atomic ion/surface collisions

Evans

Pradeep

Shen

et al. 1999

Rapid Commun. Mass Spectrom.

View full text Add to dashboard Cite

The transition metal ions, Cr Á , Mo Á , W Á and Re , abstract one or more fluorine atoms or C m F n groups (m = 1,2; n = 1-5) in collisions with fluorocarbon self-assembled monolayers (F-SAMs). The number of atoms abstracted increases with collision energy, and with W Á and Re it is possible to maximize a specific scattered product ion by selecting the appropriate collision energy. The collision energy dependence suggests that dissociation of the products of multiple abstractions is not an important source of any of the observed ion/surface reaction products. The ions W Á and Re activate and insert into C-C as well as C-F bonds. In Re collisions, products of C-C bond activation are of comparable intensity to the C-F activation products. The reactivity of the ions towards fluorine abstraction is observed to be Cr Á `Mo Á `WÁ `Re . The data are interpreted in terms of reaction at the surface and are rationalized by considering three factors (i) the electronic structures of the ions, (ii) the thermochemistry of fluorine abstraction, and (iii) the degree of orbital overlap of the metal ion and the F-SAM substrate.

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C−F Bond Cleavage by Mass-Selected Free Radicals at Fluorinated Self-Assembled Monolayer Surfaces

Cited by 13 publications

References 34 publications

C-F and C-C bond activation by transition metals in low energy atomic ion/surface collisions

C-F and C-C bond activation by transition metals in low energy atomic ion/surface collisions

Chemical modification of fluorinated self-assembled monolayer surfaces using low-energy ion beams for halogen and pseudohalogen transfer

C–F and C–C bond activation by transition metals in low energy atomic ion/surface collisions

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