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Severeyns, An; Vos, Dirk De; Jacobs, Pierre

doi:10.1023/a:1013845619179

Cited by 20 publications

(14 citation statements)

References 35 publications

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“…Surprisingly, although osmium-catalyzed oxidation reactions of olefins [63][64][65][66][67][68][69][70][71][72][73] and alcohols [74][75][76][77][78] have been reported and are used in organic synthesis, much less is known about catalysis of alkane transformations by soluble osmium compounds [79][80][81][82]. Oxide of high-valent osmium, OsO 4 [79], and osmium chlorides [80] have been used in alkane oxidations with hydrogen peroxide in organic solvents.…”

Section: Introductionmentioning

confidence: 99%

Oxidations catalyzed by osmium compounds. Part 1: Efficient alkane oxidation with peroxides catalyzed by an olefin carbonyl osmium(0) complex

Shul’pin¹,

Kudinov²,

Shul’pina³

et al. 2006

Journal of Organometallic Chemistry

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Section: Introductionmentioning

confidence: 99%

Oxidations catalyzed by osmium compounds. Part 1: Efficient alkane oxidation with peroxides catalyzed by an olefin carbonyl osmium(0) complex

Shul’pin¹,

Kudinov²,

Shul’pina³

et al. 2006

Journal of Organometallic Chemistry

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“…However, the related aliphatic alkenes did not show this isomerization process (entries 8 and 9), and only the syn-dihydroxylation products were detected for the reaction of (Z)-and (E)-hex-3-ene. Excellent results were achieved when aliphatic alkenes were tested, with independence of the nature of the alkene, such as terminal or internal (entries [8][9][10][11][12][13][14][15]. The tolerance of other functional groups was also tested using allylic ether or ester moieties, obtaining the corresponding diol with similar results (entries 16 and 17).…”

Section: Dihydroxylation Reactionsmentioning

confidence: 92%

“…In the last years a great effort has been made to prepare heterogeneous catalysts [7][8][9][10][11] which overcome these problems. Different supports having osmium salts in different loadings (osmium/support ratio), such as polymers (0.25-5 mol%) [12][13][14][15], silica (0.25 mol%) [16], cinchona modified silica gel (1 mol%) [17][18][19], hydrotalcites (8.5 mol%) [20,21], dendrimers (0.25-1 mol%) [22,23], polysiloxane (1 mol%) [24], imigolite (0.25 mol%) [25] fullerenes (3.8 mol %) [26], magnetically recoverable quaternary ammonium salts (2 mol%) [27], or zeolites (0.6 mol%) [28] have been reported for this purpose, as well as other strategies including microencapsulation (5 mol%) [29][30][31], ionexchange technique (0.5-2.5 mol%) [32][33][34][35], and the use of poly(ethylene glycol) (0.5 mol%) [36] or ionic liquids (0.5-2 mol%) [37,38].…”

Section: Introductionmentioning

confidence: 99%

Osmium impregnated on magnetite as a heterogeneous catalyst for the syn-dihydroxylation of alkenes

Cano

Pérez

Ramón

2014

Applied Catalysis A: General

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Easy preparation of a novel magnetic nanocatalyst.Simple catalyst removing by an external magnetic field. The lowest catalyst loading reported for this transformationThe use of complicated and expensive organic ligands, used in related processes, is avoided AbstractA new catalyst derived from osmium has been prepared, fully characterized and tested in the dihydroxylation of alkenes. The catalyst was prepared by wet impregnation methodology of OsCl 3 •3H 2 O on a commercial micro-magnetite surface. The catalyst allowed the reaction with one of the lowest osmium loadings for a heterogeneous catalyst and was selective for the monodihydroxylation of 1,5-dienes. Moreover, the catalyst was easily removed from the reaction medium by the simple use of a magnet. The selectivity of catalyst is very high with conversions up to 99%. Preliminary kinetics studies showed a first-order reaction rate with respect to the catalyst.

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“…An alternative, conceptual approach is rooted in the reaction mechanism of the cis-dihydroxylation, which comprises two stages: (i) the attack of the Os(VIII) cisdioxo complex on the olefin; and (ii) the reoxidation of Os(VI) to Os(VIII) with the hydrolytic release of the diol [149,150]. The immobilization is based on two particular properties of the Os diolate species involved in the dihydroxylation cycle.…”

Section: B Immobilization Of W Via P − O − W Interactionsmentioning

confidence: 99%

Oxidations on Immobilized Molecular Catalysts

Wahlen

Vos

2008

Handbook of Heterogeneous Catalysis

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IntroductionThe immobilization of homogeneous catalysts has been the focal point of extensive research effort over the past few decades. Heterogenization facilitates separation of the catalyst from the reagents and products, simplifies the recovery of the often expensive or toxic catalysts, and also allows the reuse or continuous operation of the immobilized catalyst. The immobilization of a homogeneous oxidation catalyst often greatly enhances its stability, due to the suppression of bimolecular deactivation pathways. For example, soluble metal complexes tend to react with each other, leading to oxidative degradation of the organic ligands. Another non-productive side reaction is the formation of inactive μ-oxo-bridged dimers. Such self-destruction and dimerization processes are almost impossible with a properly immobilized complex. Many approaches allow the careful control of metal complex loading of the support, and often truly site-isolated metal centers are obtained. Moreover, immobilization sometimes leads to an improved activity of the catalyst. For example, the microenvironment of the catalytic center may provide the correct polarity and acidobasicity for the desired catalytic activity. * Corresponding author.In this chapter, existing immobilization techniques are reviewed with special focus on their application in liquid-phase catalytic oxidations. General aspects such as the type of metal and oxidant, the choice of support, and the issue of leaching are discussed. The discussion is limited to the immobilization of achiral oxidation catalysts; chiral catalysts and metal-free organic catalysts are not included. The focus is on reactions employing clean, inexpensive oxidants such as molecular oxygen, hydrogen peroxide, or organic peroxides. Finally, the concepts are illustrated with examples selected among early seminal work and more recent publications. Only synthetically useful oxidative transformations of organic compounds are discussed; bleaching or deep oxidation of organics and oxidation of inorganic compounds are not included. Solid catalytic materials are only discussed if there exist homogeneous analogues for these materials. The immobilization of nanoclusters (e.g., Au, Pd) is not included, however. Emphasis is placed on examples where the heterogeneous nature of the catalysis has clearly been proven, preferably by employing stringent filtration tests. Immobilization MethodsIn designing an immobilization method for homogeneous oxidation catalysts, it is preferable to first have a clear idea of all chemical states of the catalyst that must be withheld by the support. This implies knowledge of the catalytic cycle, and of all metal species in the system. Only then can a mechanism for catalyst immobilization be proposed which is effective for all chemical states of the metal involved, particularly for the most oxidized form of the redox metal. Although this is a more demanding approach, it may often be the only rewarding method [1].Several different methodologies and concepts may be followed to achie...

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Cited by 20 publications

References 35 publications

Oxidations catalyzed by osmium compounds. Part 1: Efficient alkane oxidation with peroxides catalyzed by an olefin carbonyl osmium(0) complex

Oxidations catalyzed by osmium compounds. Part 1: Efficient alkane oxidation with peroxides catalyzed by an olefin carbonyl osmium(0) complex

Osmium impregnated on magnetite as a heterogeneous catalyst for the syn-dihydroxylation of alkenes

Oxidations on Immobilized Molecular Catalysts

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