ESCA and X-ray spectral study of Pd(0), Pd(I) and Pd(II) compounds with triphenylphosphine ligands

Nefedov, V. I.; Salyn, Ya. V.; Моисеев, И. И.; Садовский, А. П.; Berenbljum, A. S.; Knizhnik, A.; Mund, S. L.

doi:10.1016/s0020-1693(00)93391-7

Cited by 56 publications

(24 citation statements)

References 6 publications

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“…The formation of the sol-gel entrapped nanoparticles is also associated with the darkening of the sol-gel matrix. The existence of most of the metal particles as Pd 0 has been confirmed by X-ray photoelectron spectroscopy (XPS), which shows distinguished binding energy peaks (BE) of Pd 3d 5/2 and 3d 3/2 at 335.58 and 340.84 eV, respectively [5] (Figure 2A). The shapes of these peaks may suggest the presence of small amounts (up to 10 %) of Pd II species.…”

Section: Resultsmentioning

confidence: 93%

On the Involvement of Palladium Nanoparticles in the Heck and Suzuki Reactions

et al. 2008

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We describe two different pathways by which palladium-catalyzed Heck and Suzuki coupling reactions take place. When sol-gel entrapped palladium acetate was used as a catalyst, the reactions proceed by the formation of metallic nanoparticles. Such particles were already formed during the immobilization of the palladium salt. Upon application of palladium derivatives of proline, tyrosine, or alanine, either in their homogeneous or in their sol-gel entrapped version, no Pd 0 particles could be detected, even when the couplings were carried out in boiling mesitylene (161°C) or during pro-

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Section: Resultsmentioning

confidence: 93%

On the Involvement of Palladium Nanoparticles in the Heck and Suzuki Reactions

et al. 2008

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“…At 423 K, most of the Pd was reduced to the element, with the expected binding energy of 335.5 eV. [15,16] The broadening at higher binding energies was evidence that some unreduced Pd remained in the sample. This may explain why the total C 1s signal intensity had not decreased by 50 % after this treatment step, as one would expect from the Pd reduction.…”

Section: Resultsmentioning

confidence: 99%

“…At 423 K, most of the Pd is reduced to the element, with the expected binding energy of 335.5 eV. [16,26] The broadening to higher binding energies is evidence that some unreduced Pd remained in the sample. The Pd binding energy is insensitive to the formation of interstitial carbon that is not a carbide.…”

Section: Discussionmentioning

confidence: 99%

The Origin of the Positive Effect of Cadmium Acetate on the Action of Supported Palladium Catalysts

et al. 1998

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“…According to the XPS data (Table , Figure ), Pd in all three samples was presented both in zero‐valent (Pd 0 , 335.0–335.7 eV at Pd 3d 5/2 ) and oxidized forms (PdO x , 336.5 eV at Pd 3d 5/2 ; PdO, 337.4 eV at Pd 3d 5/2 ), that is typical for catalyst stored in the air and containing N‐ and O‐coordination groups in their structures –,. Nonetheless, the distribution of the latters was significantly dependent on the carrier structure for the certain catalyst.…”

Section: Resultsmentioning

confidence: 97%

Dendrimer‐Encapsulated Pd Nanoparticles, Immobilized in Silica Pores, as Catalysts for Selective Hydrogenation of Unsaturated Compounds

et al. 2019

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Heterogeneous Pd‐containing nanocatalysts, based on poly (propylene imine) dendrimers immobilized in silica pores and networks, obtained by co‐hydrolysis in situ, have been synthesized and examined in the hydrogenation of various unsaturated compounds. The catalyst activity and selectivity were found to strongly depend on the carrier structure as well as on the substrate electron and geometric features. Thus, mesoporous catalyst, synthesized in presence of both polymeric template and tetraethoxysilane, revealed the maximum activity in the hydrogenation of various styrenes, including bulky and rigid stilbene and its isomers, reaching TOF values of about 230000 h −1 . Other mesoporous catalyst, synthesized in the presence of polymeric template, but without addition of Si(OEt) 4 , provided the trans ‐cyclooctene formation with the selectivity of 90–95 %, appearing as similar to homogeneous dendrimer‐based catalysts. Microporous catalyst, obtained only on the presence of Si(OEt) 4 , while dendrimer molecules acting as both anchored ligands and template, demonstrated the maximum activity in the hydrogenation of terminal linear alkynes and conjugated dienes, reaching TOF values up to 400000 h −1 . Herein the total selectivity on alkene in the case of terminal alkynes and conjugated dienes reached 95–99 % even at hydrogen pressure of 30 atm. The catalysts synthesized can be easily isolated from reaction products and recycled without significant loss of activity.

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ESCA and X-ray spectral study of Pd(0), Pd(I) and Pd(II) compounds with triphenylphosphine ligands

Cited by 56 publications

References 6 publications

On the Involvement of Palladium Nanoparticles in the Heck and Suzuki Reactions

On the Involvement of Palladium Nanoparticles in the Heck and Suzuki Reactions

The Origin of the Positive Effect of Cadmium Acetate on the Action of Supported Palladium Catalysts

Dendrimer‐Encapsulated Pd Nanoparticles, Immobilized in Silica Pores, as Catalysts for Selective Hydrogenation of Unsaturated Compounds

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