A DFT Exploration of Efficient Catalysts Based on Metal‐Salen Monomers for the Cycloaddition Reaction of CO<sub>2</sub> to Propylene Oxide

Wu, Tao; Wang, Tingting; Sun, Lei; Deng, Kaiming; Deng, Weiqiao; Lu, Ruifeng

doi:10.1002/slct.201700043

Cited by 18 publications

(8 citation statements)

References 44 publications

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“…It was also shown that Mn III salen complexes are not detrimental to the epoxide yield in these conditions while Cr III -salophen-CO 2 H leads to more epoxide ring opening as the result of its higher Lewis acidity compared to Mn III . The ability of Cr III -salophen-CO 2 H to activate epoxides 33 and our previous results on the cycloaddition of CO 2 onto styrene oxide using Cr III -salophen-CO 2 H (ref.…”

Section: One-pot Oxidative Carboxylation Of Styrene Using Co 2 and Osupporting

confidence: 61%

Revisiting the Mukaiyama-type epoxidation for the conversion of styrene into styrene carbonate in the presence of O₂ and CO₂

et al. 2023

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Section: One-pot Oxidative Carboxylation Of Styrene Using Co 2 and Osupporting

confidence: 61%

Revisiting the Mukaiyama-type epoxidation for the conversion of styrene into styrene carbonate in the presence of O₂ and CO₂

et al. 2023

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“…The Co(III)K(I) catalyst is a rare example of a dinuclear complex active using propylene oxide/carbon dioxide and operating without any cocatalyst. Regardless of the catalyst structure, there are very few other investigations into the PO/CO 2 ROCOP mechanism, the majority of studies apply DFT calculations to investigate specific steps such as epoxide binding, CO 2 insertion, − chain dissociation, or backbiting reactions, independent of the complete cycle. One rationale for these “simplified” investigations is that the presence of the cocatalyst complicates the active site speciation.…”

Section: Resultsmentioning

confidence: 99%

Insights into the Mechanism of Carbon Dioxide and Propylene Oxide Ring-Opening Copolymerization Using a Co(III)/K(I) Heterodinuclear Catalyst

et al. 2022

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A combined computational and experimental investigation into the catalytic cycle of carbon dioxide and propylene oxide ring-opening copolymerization is presented using a Co(III)K(I) heterodinuclear complex (Deacy, A. C.et al. Co(III)/ Alkali-Metal(I) Heterodinuclear Catalysts for the Ring-Opening Copolymerization of CO 2 and Propylene Oxide. J. Am. Chem. Soc. 2020, 142(45), 19150−19160). The complex is a rare example of a dinuclear catalyst, which is active for the copolymerization of CO 2 and propylene oxide, a large-scale commercial product. Understanding the mechanisms for both product and byproduct formation is essential for rational catalyst improvements, but there are very few other mechanistic studies using these monomers. The investigation suggests that cobalt serves both to activate propylene oxide and to stabilize the catalytic intermediates, while potassium provides a transient carbonate nucleophile that ringopens the activated propylene oxide. Density functional theory (DFT) calculations indicate that reverse roles for the metals have inaccessibly high energy barriers and are unlikely to occur under experimental conditions. The rate-determining step is calculated as the ring opening of the propylene oxide (ΔG calc † = +22.2 kcal mol −1 ); consistent with experimental measurements (ΔG exp † = +22.1 kcal mol −1 , 50 °C). The calculated barrier to the selectivity limiting step, i.e., backbiting from the alkoxide intermediate to form propylene carbonate (ΔG calc † = +21.4 kcal mol −1 ), is competitive with the barrier to epoxide ring opening (ΔG calc † = +22.2 kcal mol −1 ) implicating an equilibrium between alkoxide and carbonate intermediates. This idea is tested experimentally and is controlled by carbon dioxide pressure or temperature to moderate selectivity. The catalytic mechanism, supported by theoretical and experimental investigations, should help to guide future catalyst design and optimization.

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“…It is noteworthy that no styrene oxide conversion was observed with these two last cocatalysts at 50 °C. This should be seen in conjunction with the DFT calculations performed by Deng and Lu's team, which concern the interactions between different metal-salophen complex monomers and propylene oxide (Wu et al, 2017). Of all the metals tested, Cr(III) was indeed found to have the highest binding energy with propylene oxide (15.4 kcal mol −1 ), higher than those of Mn(III) and Ni(II), although not higher than the desorption energy of the products.…”

Section: Synthesis and Characterization Of The Co-catalystsmentioning

confidence: 83%

Chromium-Salophen as a Soluble or Silica-Supported Co-Catalyst for the Fixation of CO2 Onto Styrene Oxide at Low Temperatures

et al. 2021

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Addition of a soluble or a supported CrIII-salophen complex as a co-catalyst greatly enhances the catalytic activity of Bu4NBr for the formation of styrene carbonate from styrene epoxide and CO2. Their combination with a very low co-catalyst:Bu4NBr:styrene oxide molar ratio = 1:2:112 (corresponding to 0.9 mol% of CrIII co-catalyst) led to an almost complete conversion of styrene oxide after 7 h at 80°C under an initial pressure of CO2 of 11 bar and to a selectivity in styrene carbonate of 100%. The covalent heterogenization of the complex was achieved through the formation of an amide bond with a functionalized {NH2}-SBA-15 silica support. In both conditions, the use of these CrIII catalysts allowed excellent conversion of styrene already at 50°C (69 and 47% after 24 h, respectively, in homogeneous and heterogeneous conditions). Comparison with our previous work using other metal cations from the transition metals particularly highlights the preponderant effect of the nature of the metal cation as a co-catalyst in this reaction, that may be linked to its calculated binding energy to the epoxides. Both co-catalysts were successfully reused four times without any appreciable loss of performance.

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A DFT Exploration of Efficient Catalysts Based on Metal‐Salen Monomers for the Cycloaddition Reaction of CO₂ to Propylene Oxide

Cited by 18 publications

References 44 publications

Revisiting the Mukaiyama-type epoxidation for the conversion of styrene into styrene carbonate in the presence of O₂ and CO₂

Revisiting the Mukaiyama-type epoxidation for the conversion of styrene into styrene carbonate in the presence of O₂ and CO₂

Insights into the Mechanism of Carbon Dioxide and Propylene Oxide Ring-Opening Copolymerization Using a Co(III)/K(I) Heterodinuclear Catalyst

Chromium-Salophen as a Soluble or Silica-Supported Co-Catalyst for the Fixation of CO2 Onto Styrene Oxide at Low Temperatures

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A DFT Exploration of Efficient Catalysts Based on Metal‐Salen Monomers for the Cycloaddition Reaction of CO2 to Propylene Oxide

Cited by 18 publications

References 44 publications

Revisiting the Mukaiyama-type epoxidation for the conversion of styrene into styrene carbonate in the presence of O2 and CO2

Revisiting the Mukaiyama-type epoxidation for the conversion of styrene into styrene carbonate in the presence of O2 and CO2

Insights into the Mechanism of Carbon Dioxide and Propylene Oxide Ring-Opening Copolymerization Using a Co(III)/K(I) Heterodinuclear Catalyst

Chromium-Salophen as a Soluble or Silica-Supported Co-Catalyst for the Fixation of CO2 Onto Styrene Oxide at Low Temperatures

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A DFT Exploration of Efficient Catalysts Based on Metal‐Salen Monomers for the Cycloaddition Reaction of CO₂ to Propylene Oxide

Revisiting the Mukaiyama-type epoxidation for the conversion of styrene into styrene carbonate in the presence of O₂ and CO₂

Revisiting the Mukaiyama-type epoxidation for the conversion of styrene into styrene carbonate in the presence of O₂ and CO₂