A Double‐Cavity‐Containing Porphyrin Host as a Highly Stable Epoxidation Catalyst

Thomassen, Paul J.; Varghese, Siby; Bijsterveld, Edward J. A.; Thordarson, Pall; Elemans, Johannes A. A. W.; Rowan, Alan E.; Nolte, Roeland J. M.

doi:10.1002/ejoc.201500492

Cited by 16 publications

(15 citation statements)

References 40 publications

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“…Multiple reports of metalloporphyrin-catalyzed oxidations suggest that high-valent metal intermediates play key roles in the oxidation of organic substrates [28][29][30]. Particularly, our previous work on manganese porphyrin-catalyzed epoxidations suggests the formation of catalytically active high-valent manganese(IV or V) oxo porphyrins [9,10,31,32]. The presence of such a reactive species was also confirmed for catalyst MnPC by monitoring the changes in the UV-vis spectra during the oxidation of cyclohexene.…”

Section: Plausible Mechanism For the Aerobic Epoxidation Catalyzed Bymentioning

confidence: 69%

Aerobic Epoxidation of Low-Molecular-Weight and Polymeric Olefins by a Supramolecular Manganese Porphyrin Catalyst

Bernar¹,

Rutjes²,

Elemans³

et al. 2019

Catalysts

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We report on the highly efficient epoxidation of low-molecular-weight and polymeric olefins catalyzed by a supramolecular manganese porphyrin complex using molecular oxygen as an oxidant and an aldehyde as a co-reductant. At ambient temperature and under optimized reaction conditions, the catalyst showed high activity and stereoselectivity. The efficiency of the supramolecular manganese porphyrin was higher than that of a reference porphyrin catalyst, possibly because it was more stable under the applied reaction conditions. Mechanistic studies suggest that a manganese oxo porphyrin complex may be an intermediate in the epoxidation reaction.

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Section: Plausible Mechanism For the Aerobic Epoxidation Catalyzed Bymentioning

confidence: 69%

Aerobic Epoxidation of Low-Molecular-Weight and Polymeric Olefins by a Supramolecular Manganese Porphyrin Catalyst

Bernar¹,

Rutjes²,

Elemans³

et al. 2019

Catalysts

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“…The TOF is doubled with the supramolecular system 3 , when compared to its model parent 4 . Progressive epoxidation of the polybutadiene thread as well as the endohedral formation of manganese‐oxo intermediate was clearly evidenced by a thorough investigation …”

Section: Confined Metal‐catalystsmentioning

confidence: 97%

Covalent Cages with Inwardly Directed Reactive Centers as Confined Metal and Organocatalysts

et al. 2018

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Covalent cages with a well‐defined cavity located close to a reactive center are of increasing interest because of their outstanding ability to mimic the catalytic properties of enzymatic systems. The size and shape of such synthetic nanosized reactors strongly affect the behavior of the trapped reaction partners, which can adopt specific conformations and orientations. In particular, the use of molecular cages with confined reactive functions strongly modifies the outcome of catalytic transformations that are carried out therein. This review article describes covalent molecular cages presenting an endohedral functionalization of their inner space and reports on their catalytic activities compared with those of model systems that lack cavity.

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“…Along our efforts to develop porphyrin double cage compounds, we previously reported on H 2 2 (Figure 1) in which a porphyrin molecule is featured to which two glycoluril cages are attached via 8 covalent bonds [50,51] . This host was found to bind two viologen guests via negative allosteric cooperativity, i. e., the second viologen was bound more than 3 orders of magnitude weaker than the first.…”

Section: Introductionmentioning

confidence: 99%

Allosteric Guest Binding in Chiral Zirconium(IV) Double Decker Porphyrin Cages

Bruekers¹,

Hellinghuizen²,

Vanthuyne

et al. 2021

Eur J Org Chem

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Chiral zirconium(IV) double cage sandwich complex Zr(1) 2 has been synthesized in one step from porphyrin cage H 2 1. Zr(1) 2 was obtained as a racemate, which was resolved by HPLC and the enantiomers were isolated in > 99.5 % ee. Their absolute configurations were assigned on the basis of X-ray crystallography and circular dichroism spectroscopy. Vibrational circular dichroism (VCD) experiments on the enantiomers of Zr(1) 2 revealed that the chirality around the zirconium center is propagated throughout the whole cage structure. The axial conformational chirality of the double cage complex displayed a VCD fingerprint similar to the one observed previously for a related chiral cage compound with planar and point chirality. Zr(1) 2 shows fluorescence, which is quenched when viologen guests bind in its cavities. The binding of viologen and dihydroxybenzene derivatives in the two cavities of Zr(1) 2 occurs with negative allostery, the cooperativity factors α (= 4 K 2 /K 1) being as low as 0.0076 for the binding of N,N'dimethylviologen. These allosteric effects are attributed to a pinching of the second cavity as a result of guest binding in the first cavity.

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A Double‐Cavity‐Containing Porphyrin Host as a Highly Stable Epoxidation Catalyst

Cited by 16 publications

References 40 publications

Aerobic Epoxidation of Low-Molecular-Weight and Polymeric Olefins by a Supramolecular Manganese Porphyrin Catalyst

Aerobic Epoxidation of Low-Molecular-Weight and Polymeric Olefins by a Supramolecular Manganese Porphyrin Catalyst

Covalent Cages with Inwardly Directed Reactive Centers as Confined Metal and Organocatalysts

Allosteric Guest Binding in Chiral Zirconium(IV) Double Decker Porphyrin Cages

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