Selective and Facile C−F Bond Activation of Trifluoromethyl Groups on Cu(111)

Hou, Ya-Ching; Chiang, Cheng-Hung

doi:10.1021/ja991596x

Cited by 21 publications

(15 citation statements)

References 18 publications

(19 reference statements)

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“…Specifically,p erfluoropentacene was absorbed to, and defluorinated by,C u(1 11 ), [7] and surface-bound Cu(1 11)-CF 3 species (formed by dissociative chemisorptiono fC F 3 I) were shown to readily form surface-bound Cu(1 11)-CF 2 species. [8] Note that these examples are distinct from the work reported here in that no molecular speciesw ere desorbed, let alone isolated,i ne ither case. In both cases carbonf ilms were ultimately formed.…”

contrasting

confidence: 54%

Copper Causes Regiospecific Formation of C₄F₈‐Containing Six‐Membered Rings and their Defluorination/Aromatization to C₄F₄‐Containing Rings in Triphenylene/1,4‐C₄F₈I₂ Reactions

Rippy

Bukovsky

Clikeman

et al. 2015

Chemistry A European J

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The presence of Cu in reactions of triphenylene (TRPH) and 1,4-C4 F8 I2 at 360 °C led to regiospecific substitution of TRPH ortho C(β) atoms to form C4 F8 -containing rings, completely suppressing substitution on C(α) atoms. In addition, Cu caused selective reductive-defluorination/aromatization (RD/A) to form C4 F4 -containing aromatic rings. Without Cu, the reactions of TRPH and 1,4-C4 F8 I2 were not regiospecific and no RD/A was observed. These results, supported by DFT calculations, are the first examples of Cu-promoted 1) regiospecific perfluoroannulation, 2) preparative C-F activation, and 3) RD/A. HPLC-purified products were characterized by X-ray diffraction, low-temperature PES, and (1) H/(19) F NMR.

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contrasting

confidence: 54%

Copper Causes Regiospecific Formation of C₄F₈‐Containing Six‐Membered Rings and their Defluorination/Aromatization to C₄F₄‐Containing Rings in Triphenylene/1,4‐C₄F₈I₂ Reactions

Rippy

Bukovsky

Clikeman

et al. 2015

Chemistry A European J

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“…It follows that C 2 F 4 is generated and desorbed during adsorption of CF 3 I, in agreement with Ref. 6. CF 3 ϩ undergoes a small increase at the start of adsorption, where the sticking probability of CF 3 I is very close to one.…”

Section: Bce On Cu"111…supporting

confidence: 88%

Line of sight techniques: Providing an inventory of all species arriving at and departing from a surface

Chan

Skegg

Jones

2001

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Articles you may be interested inElectron induced dissociation of trimethyl (methylcyclopentadienyl) platinum (IV): Total cross section as a function of incident electron energy Adsorption and reaction of methanol on clean and oxygen modified rhodium/vanadium surface alloys Line of sight ͑LOS͒ techniques comprise those methods in which species emanating from a surface ͑atoms, molecules, and radicals͒ undergo just a single pass through the ionization volume of a mass spectrometer before being pumped. This is achieved by enclosing the mass spectrometer within a cryoshield fitted with appropriate apertures, such that line of sight is established only between a patch on the sample surface ͑Ϸ7 mm diameter͒ and the ionization volume. All LOS techniques are free from extraneous signals and have approximately equal detection probabilities for all species. Line of sight temperature programmed desorption, sticking probability ͑LOSSP͒, and product desorption ͑LOSPD͒ provide powerful and reliable ways of studying all aspects of surface kinetics, by allowing an inventory of all species arriving at and departing from a surface, for any combination of partial pressures, surface temperature, surface composition, and surface structure. Here we illustrate LOSSP and LOSPD using the reactions of 1-bromo-2-chloroethane, BrCH 2 CH 2 Cl,͑BCE͒ and iodotrifluoromethane, CF 3 I, on Cu͑111͒. For BCE we show that there is a 1:1 correspondence of product ethene to reactant BCE during dissociative adsorption at TϾ253 K, and that the dissociative adsorption is nonactivated with a transition state 11Ϯ2.5 kJ mol Ϫ1 below zero ͑0ϭmolecule at infinity͒. For CF 3 I dissociative adsorption occurs at room temperature with a sticking probability of 0.96Ϯ0.02 to produce CF 2 • which can either desorb as gaseous CF 2 • radicals ͑observed͒ or undergo a coupling reaction and then desorb as gaseous C 2 F 4 ͑also observed͒. No other gas phase products were observed.

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“…Previously, we performed an ultrahigh vacuum (UHV) surface science study to demonstrate that chemisorbed CF 3 formed on Cu(111) led to the evolution of CF 2 dCF 2 as the main gas-phase product upon heating the surface to 250 K in temperature programmed reaction/ desorption (TPR/D). 2 This observation inferred the existence of difluorocarbene bonded to the metal surface. Thus, the role of Burton's organometallic reagent, serving as the source of CF 2 units, was adequately modeled.…”

mentioning

confidence: 93%

Direct Observation of CF₂ Insertion into the Carbon−Metal Bond on Cu(111)

and

Chiang

2003

J. Phys. Chem. B

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Reflection-absorption infrared spectroscopy determined the coexistence of surface-bound trifluoromethyl (CF 3 ) and difluorocarbene (CF 2 ) moieties, resulting from C-I and subsequent C-F bond scission reactions below 160 K after the CF 3 I adsorption on Cu(111). Upon further heating, concomitant with the depletion of Cu-CF 3 and CudCF 2 , a new surface intermediate was identified unequivocally as the pentafluoroethyl (Cu-CF 2 CF 3 ) groups. This observation provides evidence for the reaction of CF 2 migratory insertion into the carbon-copper bond. At about 300 K, together with the CF 2 coupling pathway, the Cu-CF 2 CF 3 species undergo a β-fluoride elimination reaction to liberate tetrafluroethylene (CF 2 dCF 2 ) into the gas-phase as the final product.

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Selective and Facile C−F Bond Activation of Trifluoromethyl Groups on Cu(111)

Cited by 21 publications

References 18 publications

Copper Causes Regiospecific Formation of C₄F₈‐Containing Six‐Membered Rings and their Defluorination/Aromatization to C₄F₄‐Containing Rings in Triphenylene/1,4‐C₄F₈I₂ Reactions

Copper Causes Regiospecific Formation of C₄F₈‐Containing Six‐Membered Rings and their Defluorination/Aromatization to C₄F₄‐Containing Rings in Triphenylene/1,4‐C₄F₈I₂ Reactions

Line of sight techniques: Providing an inventory of all species arriving at and departing from a surface

Direct Observation of CF₂ Insertion into the Carbon−Metal Bond on Cu(111)

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Selective and Facile C−F Bond Activation of Trifluoromethyl Groups on Cu(111)

Cited by 21 publications

References 18 publications

Copper Causes Regiospecific Formation of C4F8‐Containing Six‐Membered Rings and their Defluorination/Aromatization to C4F4‐Containing Rings in Triphenylene/1,4‐C4F8I2 Reactions

Copper Causes Regiospecific Formation of C4F8‐Containing Six‐Membered Rings and their Defluorination/Aromatization to C4F4‐Containing Rings in Triphenylene/1,4‐C4F8I2 Reactions

Line of sight techniques: Providing an inventory of all species arriving at and departing from a surface

Direct Observation of CF2 Insertion into the Carbon−Metal Bond on Cu(111)

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Copper Causes Regiospecific Formation of C₄F₈‐Containing Six‐Membered Rings and their Defluorination/Aromatization to C₄F₄‐Containing Rings in Triphenylene/1,4‐C₄F₈I₂ Reactions

Copper Causes Regiospecific Formation of C₄F₈‐Containing Six‐Membered Rings and their Defluorination/Aromatization to C₄F₄‐Containing Rings in Triphenylene/1,4‐C₄F₈I₂ Reactions

Direct Observation of CF₂ Insertion into the Carbon−Metal Bond on Cu(111)