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Hage, Ronald; Krijnen, Bert; Warnaar, Johann B.; Hartl, František; Stufkens, Derk J.; Snoeck, Theo L.

doi:10.1021/ic951442s

Cited by 12 publications

(18 citation statements)

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“…Indeed, the modes associated with the Mn IV (μ‐O) 3 Mn IV and Mn III (μ‐O)(μ‐RCO 2 ) 2 Mn III cores of 1 and 2a , respectively, dominate the resonance Raman spectra recorded at λ exc = 355 (Figures S4 and S5) and 457 nm at the same concentrations (1 m M ) as that employed17,18 in the catalytic oxidation of alkenes (vide infra). The resonance Raman spectrum of 1 was reported previously (in the solid state, λ exc = 457 nm) by Hage et al21 and showed enhancement of a band at $\tilde {\nu}$ = 700 cm –1 assigned to the ν sym (Mn–O–Mn) mode on the basis of 18 O labelling results. The Raman spectra of 1 in CH 3 CN with λ exc = 355 and 457 nm show resonance enhancement primarily of low‐wavenumber modes (<900 cm –1 ) consistent with a μ‐oxido to Mn IV ligand‐to‐metal charge‐transfer (LMCT) band.…”

Section: Resultssupporting

confidence: 64%

“…For the spectra of aliquots five and six, a very weak signal is observed that can be assigned tentatively to a 16‐line species (the hyperfine coupling value a is ca. 76 G) 21. Between aliquots seven and nine, the characteristic six‐line signal of an octahedral high‐spin Mn II species appears and increases in intensity concomitant with the decrease and recovery in absorbance at λ = 532 nm.…”

Section: Resultsmentioning

confidence: 98%

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Mechanistic Links in the in‐situ Formation of Dinuclear Manganese Catalysts, H₂O₂ Disproportionation, and Alkene Oxidation

et al. 2015

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The oxidation of substrates, such as alkenes, with H2O2 and the catalyst [MnIV2(μ‐O)3(tmtacn)2]2+ (1; tmtacn = 1,4,7‐trimethyl‐1,4,7‐triazacyclononane) is promoted by the addition of carboxylic acids through the in situ formation of bis(carboxylato) complexes of the type [MnIII2(μ‐O)(μ‐RCO2)2(tmtacn)2]2+. The conversion of 1 to these complexes requires a complex series of redox reactions coupled with the overall exchange of μ‐oxido ligands for μ‐carboxylato ligands. Here, we show that the mechanism by which this conversion occurs holds implications with regard to the species that is directly engaged in the catalytic oxidation of alkenes. Through a combination of UV/Vis absorption, Raman, resonance Raman and electron paramagnetic resonance (EPR) spectroscopy, it is shown that the conversion proceeds by an autocatalytic mechanism and that the species that engages in the oxidation of organic substrates also catalyses H2O2 decomposition, and the former process is faster.

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Section: Resultssupporting

confidence: 64%

Section: Resultsmentioning

confidence: 98%

Mechanistic Links in the in‐situ Formation of Dinuclear Manganese Catalysts, H₂O₂ Disproportionation, and Alkene Oxidation

et al. 2015

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“…The species CsʲCo 4 Ru 3 is of further interest as a face-capping tridentate ligand, which should allow it to be deployed broadly. Facecapping N 3 ligands have played a significant role in coordination chemistry, and catalysis as exemplified by extensive work on 1,4,7-triazacyclonane (22,23) and tris(pyrazoyl)borate (24).…”

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confidence: 99%

Systematic assembly of the double molecular boxes: {Cs⊂[CpCo(CN)₃]₄[Cp*Ru]₃} as a tridentate ligand

Contakes

Kuhlman

Ramesh

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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T he design of molecular containers represents an important component of nanotechnology and has attracted intense interest from synthetic chemists (1-4). Research on molecular containers can realistically be expected to provide highly selective sensors, sorters, and catalysts for numerous applications. A significant challenge in this area is the development of containers that are stereochemically rigid, because rigidity is the basis of sterically governed selectivity. Rigidity, however, is incompatible with much of organic chemistry, and this dichotomy is problematic because organic (and organometallic) chemistry provides the most versatile construction tools for the synthesis of molecular containers. In this contribution, we address this dichotomy, i.e., the incorporation of organic motifs into rigid frameworks. Our approach involves a hybridization of organometallic chemistry and well established precedents in the chemistry of metal cyanides.Cyanometallates are metal complexes with the general formula L l M m (CN) n . The most important cyanometallate is Prussian blue (PB), an inorganic polymer with the formula Fe 7 (CN) 18 (H 2 O) x (x ϳ 15) (5). The synthesis of this useful solid arises from the condensation of [Fe(CN) 6 ] 4Ϫ and Fe(III) salts (Eq. 1).The structure of PB may be roughly described as interconnected cubic cage subunits with Fe vertices linked by cyanide. The PB structure is in fact complicated because the otherwise idealized cubic framework is interrupted by vacancies at the metal positions, these vacancies being occupied by water molecules (6). A building block approach is inherent in Eq. 1, i.e., the use of preassembled [Fe(CN) In recent years we have developed families of molecular cyanometallate ensembles that are synthesized analogously to PB, except that our molecular building blocks are tricyanometallates wherein the three cyanide ligands are mutually cis. Half of the coordination sphere of these tricyanometallates is occupied by a strongly coordinating nondisplaceable coligand. The face-capping coligand inhibits the formation of polymers by minimizing crosslinking but still promotes the formation of three-dimensional structures, which resemble subunits of PB. Particularly effective as face-capping ligands are cyclopentadienyl, C 5 H 5 (Cp), and its pentamethyl analogue, C 5 Me 5 (pentamethylcyclopentadienyl, Cp*). In a proof of concept experiment, we showed that [CpCo (CN

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“…By analogy with manganese porphyrin and permanganate chemistry, the obvious candidates for the active catalytic species are high-valent manganese-oxo species as well as radical intermediates (the latter being readily excluded by the retention of stereochemistry observed during catalysis). The first concerted efforts to explore the mechanistic aspects of the catalysis were reported by Hage and coworkers [119], who identified the formation of carboxylic acid-bridged dinuclear manganese complexes upon reduction of 6 in aqueous media and by Lindsay-Smith and coworkers in their studies on the oxidation of cinnamates in buffered aqueous media, primarily using mass spectrometry [94i,k, 120,121,122].…”

Section: Triazacyclononane Derivativesmentioning

confidence: 99%

Manganese‐Catalyzed Oxidation with Hydrogen Peroxide

Browne

Böer

Pijper

et al. 2010

Modern Oxidation Methods

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Abstract: Page 4976. In Figure 4A, the abscissa scale should be as follows: 0.5, 0.0, -0.5, -1.0 V vs Fc/Fc + .

Cited by 12 publications

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Mechanistic Links in the in‐situ Formation of Dinuclear Manganese Catalysts, H₂O₂ Disproportionation, and Alkene Oxidation

Mechanistic Links in the in‐situ Formation of Dinuclear Manganese Catalysts, H₂O₂ Disproportionation, and Alkene Oxidation

Systematic assembly of the double molecular boxes: {Cs⊂[CpCo(CN)₃]₄[Cp*Ru]₃} as a tridentate ligand

Manganese‐Catalyzed Oxidation with Hydrogen Peroxide

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Abstract: Page 4976. In Figure 4A, the abscissa scale should be as follows: 0.5, 0.0, -0.5, -1.0 V vs Fc/Fc + .

Cited by 12 publications

References 0 publications

Mechanistic Links in the in‐situ Formation of Dinuclear Manganese Catalysts, H2O2 Disproportionation, and Alkene Oxidation

Mechanistic Links in the in‐situ Formation of Dinuclear Manganese Catalysts, H2O2 Disproportionation, and Alkene Oxidation

Systematic assembly of the double molecular boxes: {Cs⊂[CpCo(CN)3]4[Cp*Ru]3} as a tridentate ligand

Manganese‐Catalyzed Oxidation with Hydrogen Peroxide

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Mechanistic Links in the in‐situ Formation of Dinuclear Manganese Catalysts, H₂O₂ Disproportionation, and Alkene Oxidation

Mechanistic Links in the in‐situ Formation of Dinuclear Manganese Catalysts, H₂O₂ Disproportionation, and Alkene Oxidation

Systematic assembly of the double molecular boxes: {Cs⊂[CpCo(CN)₃]₄[Cp*Ru]₃} as a tridentate ligand