Metallacyclen des zirkonocens

Alt, Helmut G.; Denner, Christine E.

doi:10.1016/0022-328x(90)85081-9

Cited by 47 publications

(20 citation statements)

References 42 publications

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“…This is an interesting result which might lead to a highly active catalyst for acrylic acid synthesis; however, the catalytic reaction has not been realized with group 6 metal based systems due to the difficulty of regenerating the zerovalent complex. There have also been several reports of the oxidative cyclization of ethylene and CO 2 utilizing other metals, but none of them produced acrylate salt catalytically. − …”

Section: Introductionmentioning

confidence: 99%

Mechanistic Investigations of the Ruthenium-Catalyzed Synthesis of Acrylate Salt from Ethylene and CO₂

et al. 2020

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Here we describe detailed mechanistic analyses of the ruthenium-catalyzed synthesis of acrylate salt from ethylene and CO2. All of the primary steps of the catalytic cycle, that is (i) oxidative cyclization of ethylene and CO2 to give ruthenalactones, (ii) thermal β-H elimination of ruthenalactones to hydrido acrylato complexes, and (iii) base-mediated generation of ethylene-coordinated, zerovalent ruthenium complexes from hydrido acrylato complexes, are found to proceed more rapidly on the more electron rich complexes. These results suggest that the last two processes proceed through the cationic ruthenium complexes generated by dissociation of carboxylate anions. As another possible pathway for the catalytic acrylate synthesis, base-promoted cleavage of a ruthenalactone to an ethylene-coordinated, zerovalent ruthenium complex is also studied, and the reaction is found to proceed smoothly, where the rate of the reaction is dependent on the basicity of the base. In contrast to the stoichiometric reactivities, electron-deficient ruthenium complexes exhibited higher activity in the catalytic acrylate synthesis.

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Section: Introductionmentioning

confidence: 99%

Mechanistic Investigations of the Ruthenium-Catalyzed Synthesis of Acrylate Salt from Ethylene and CO₂

et al. 2020

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“…On treatment of 2 with CO 2 (0.1 MPa) in DMA at 60 °C, the five-membered ruthenalactone 3 was found to be produced smoothly in 71% yield (Scheme a). Formation of five-membered metallalactones by oxidative cyclization of ethylene and CO 2 has been studied to realize acrylic acid synthesis employing various transition-metal complexes. ,,− However, the isolation and identification of the resulting five-membered metallalactone intermediates were limited to Ti, Zr, V, and Ni ,− complexes, and the catalytic synthesis of an acrylate salt from ethylene and CO 2 was only recently achieved by using a Ni or Pd catalyst. , This is the first example of the formation and isolation of a ruthenalactone via oxidative cyclization involving CO 2 . As a byproduct, the corresponding carbonatoruthenium(II) 4 was observed in 7% yield. , …”

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confidence: 99%

Reactivity of a Ruthenium(0) Complex Bearing a Tetradentate Phosphine Ligand: Applications to Catalytic Acrylate Salt Synthesis from Ethylene and CO₂

2018

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By using a zerovalent, electron-rich ruthenium complex bearing a tetradentate phosphine ligand, a fivemembered ruthenalactone was generated by oxidative cyclization of ethylene and CO 2 . This ruthenalactone underwent thermal, reversible β-H elimination to afford an acrylato(hydrido)ruthenium(II) complex, which liberated acrylate salt on treatment with a base. The reaction was successfully applied to the first ruthenium-catalyzed synthesis of an acrylate salt from ethylene and CO 2 . This study demonstrated the feasibility of the electron-rich ruthenium(0) complex as a catalyst in CO 2 -fixation chemistry.

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“…Oxidative coupling of CO 2 and ethylene with a reduced transition metal complex to form a five-membered metallalactone is the most well studied method for the synthesis of acrylic acid. Examples of this approach have been demonstrated with Ni, , Mo, W, Ti, V, Zr, Fe, Pd, and Rh . However, the resulting metallacycles are typically resistant to β-hydrogen elimination or do not release free acrylic acid due to strong metal–oxygen bonds. , Lewis acids have been shown to promote β-hydride elimination, often leading to ring contraction through reinsertion to the corresponding four-membered metallalactones …”

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Iron-Mediated Coupling of Carbon Dioxide and Ethylene: Macrocyclic Metallalactones Enable Access to Various Carboxylates

et al. 2018

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Treatment of (PDI)Fe(N) (PDI, 2,6-(2,6-iPrCHN═CMe)CHN) with CO and ethylene resulted in the formation of a homologous series of saturated and unsaturated iron carboxylate products, (PDI)Fe(OCR), the distribution of which depends on the ratio of the reagents. The solid-state and electronic structures of a saturated product, (PDI)Fe(OCCH), were elucidated. Product distributions, deuterium labeling studies, and stoichiometric experiments support initial formation of a five-membered metallalactone intermediate, which undergoes subsequent ethylene insertions to generate macrocyclic metallalactones. Competitive β-hydride elimination, CO insertion, or reaction with H determines the fate of the metallalactone, the latter accounting for formation of iron complexes with saturated carboxylates. Similar reactivity was observed upon addition of propiolactone and ethylene to (PDI)Fe(N), supporting C-O oxidative addition and C-C bond formation through metallacycle intermediates.

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Metallacyclen des zirkonocens

Cited by 47 publications

References 42 publications

Mechanistic Investigations of the Ruthenium-Catalyzed Synthesis of Acrylate Salt from Ethylene and CO₂

Mechanistic Investigations of the Ruthenium-Catalyzed Synthesis of Acrylate Salt from Ethylene and CO₂

Reactivity of a Ruthenium(0) Complex Bearing a Tetradentate Phosphine Ligand: Applications to Catalytic Acrylate Salt Synthesis from Ethylene and CO₂

Iron-Mediated Coupling of Carbon Dioxide and Ethylene: Macrocyclic Metallalactones Enable Access to Various Carboxylates

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Metallacyclen des zirkonocens

Cited by 47 publications

References 42 publications

Mechanistic Investigations of the Ruthenium-Catalyzed Synthesis of Acrylate Salt from Ethylene and CO2

Mechanistic Investigations of the Ruthenium-Catalyzed Synthesis of Acrylate Salt from Ethylene and CO2

Reactivity of a Ruthenium(0) Complex Bearing a Tetradentate Phosphine Ligand: Applications to Catalytic Acrylate Salt Synthesis from Ethylene and CO2

Iron-Mediated Coupling of Carbon Dioxide and Ethylene: Macrocyclic Metallalactones Enable Access to Various Carboxylates

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Mechanistic Investigations of the Ruthenium-Catalyzed Synthesis of Acrylate Salt from Ethylene and CO₂

Mechanistic Investigations of the Ruthenium-Catalyzed Synthesis of Acrylate Salt from Ethylene and CO₂

Reactivity of a Ruthenium(0) Complex Bearing a Tetradentate Phosphine Ligand: Applications to Catalytic Acrylate Salt Synthesis from Ethylene and CO₂