Palladacycles in catalysis – a critical survey

Beletskaya, I. P.; Cheprakov, Andrei V.

doi:10.1016/j.jorganchem.2004.07.054

Cited by 490 publications

(208 citation statements)

References 139 publications

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“…The drop in catalytic activity occurs most likely due to the disproportionation of the active 14 e − -PdL 2 complex to a stable PdL 3 and an instable PdL complex. The latter aggregates to clusters, which account for the discoloration of the fluorous phase [18].…”

Section: Resultsmentioning

confidence: 99%

Palladium-Catalyzed Carbon-Carbon Cross-Coupling Reactions in Thermomorphous Double Emulsions

Misuk¹,

Mai²,

Γιαννόπουλος³

et al. 2015

J Flow Chem

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The method of combining the concept of fluorous biphasic catalysis (FCB) with micro multiple emulsions benefits from the advantages of homogeneous as well as from heterogeneous catalysis in continuous micro flow. In this particular case, three immiscible fluid phases in continuous micro segmented flow were used to perform palladium-catalyzed Heck crosscoupling reactions of styrene with aryl halides. A capillary tube-in-tube coaxial flow setup in combination with a glass micro reactor was used to produce monodisperse aqueous phase/organic phase/perfluorinated phase double emulsions. The resulting emulsions had a core-shell droplet structure composed of a perfluorcarbon fluid in which a palladium catalyst with fluorinated phosphine ligands was dissolved, an organic phase consisting of a solvent and two reagents, and an alkaline aqueous solution. The fluorous and organic phases of the double emulsion form a thermomorphous system which can be converted into one phase by an increase of temperature above 150°C, and the catalytic reaction is performed temporarily. By decreasing the temperature, a phase separation takes place; after that, the organic phase contains the product and the catalyst is located in the fluorous phase. The separated catalyst solution was reused several times without a noticeable loss of activity. The main advantage of this method is to use temporarily very high catalyst concentrations in each droplet, while employing only small amounts of the catalyst for the overall reaction volume.

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Section: Resultsmentioning

confidence: 99%

Palladium-Catalyzed Carbon-Carbon Cross-Coupling Reactions in Thermomorphous Double Emulsions

Misuk¹,

Mai²,

Γιαννόπουλος³

et al. 2015

J Flow Chem

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“…Palladium based compounds appear to be outstanding catalysts in the C−C cross−coupling reactions [2], and although there are commercially available catalysts such as [Pd(PPh3)4] or [Pd(OAc)2], they fail to comply with air and thermal stability, so by tuning the ligands this problem can be overcome. Thiosemicarbazones are a family of ligands formed by the reaction between a carbonyl group and a tiosemicarbazide.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and catalytic study in the Suzuki-Miyaura reaction of a family of palladium compounds

Martinez

Fernández-Figueiras

Reigosa

et al. 2017

Proceedings of the 21st International Electronic Conference on Synthetic Organic Chemistry

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Abstract:Thiosemicarbazone ligands are known for their versatility towards metal coordination, forming very stable compounds with metals such as palladium. In addition, palladium derivatives are used more often than not as catalyst in C-C cross coupling reactions like the Suzuki-Miyaura reaction, however the commercially available catalyst are not of much air or thermal stability. That is the reason why in this communication we present the synthesis, characterisation and catalytic study of a family of palladium -thiosemicarbazone compounds as an improvement to the thermal and air stability of commercial catalyst.

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“…[9][10][11][12] Early catalysts were homogeneous 13,14 and contained ligands such as phosphines, 15,16 pincer, 17,18 or N-heterocyclic carbenes. 19,20 A shift toward palladium nanoparticles has been apparent in the past decade because they offer the benefits of heterogeneous catalysis.…”

Section: Introductionmentioning

confidence: 99%

A mechanistic study of cross-coupling reactions catalyzed by palladium nanoparticles supported on polyaniline nanofibers

Lemke

Kaner

Diaconescu

2015

Inorg. Chem. Front.

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Palladium nanoparticles supported by polyaniline nanofibers were used as pre-catalysts for C-C cross-coupling reactions of aryl chlorides in water. Using regular techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) in conjunction with reactivity studies, we determined that a homogeneous mechanism is operating. The appearance of palladium nanoparticles and polyaniline nanofibers changes after each reaction accompanied by changes in the palladium oxidation state. Our methods could not rule out the contribution of a heterogeneous mechanism or indicate its extent.

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Palladacycles in catalysis – a critical survey

Cited by 490 publications

References 139 publications

Palladium-Catalyzed Carbon-Carbon Cross-Coupling Reactions in Thermomorphous Double Emulsions

Palladium-Catalyzed Carbon-Carbon Cross-Coupling Reactions in Thermomorphous Double Emulsions

Synthesis and catalytic study in the Suzuki-Miyaura reaction of a family of palladium compounds

A mechanistic study of cross-coupling reactions catalyzed by palladium nanoparticles supported on polyaniline nanofibers

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