27607-33-6Relevant articles and documents
A hierarchically ordered porous novel vanado-silicate catalyst for highly efficient oxidation of bulky organic molecules
Sen, Tapas,Whittle, Jacob,Howard, Matthew
, p. 4232 - 4234 (2012)
A novel hierarchically ordered porous vanado-silicate nanocomposite with interconnecting macroporous windows and meso-microporous walls containing well dispersed vanadyl species has been fabricated and used as a heterogeneous catalyst for the oxidation of a bulky organic molecule, namely cyclooctene.
cis-Dihydroxylation and epoxidation of alkenes by [Mn2O(RCO 2)2(tmtacn)2]: Tailoring the selectivity of a highly H2O2-efficient catalyst
De Boer, Johannes W.,Brinksma, Jelle,Browne, Wesley R.,Meetsma, Auke,Alsters, Paul L.,Hage, Ronald,Feringa, Ben L.
, p. 7990 - 7991 (2005)
The carboxylic acid promoted cis-dihydroxylation and epoxidation of alkenes catalyzed by [MnIV2O3(tmtacn)2]2+ 1 employing H2O2 as oxidant is described. The use of carboxylic acids at cocatalytic levels not only is effective in suppressing the inherent catalase activity of 1, but also enables the tuning of the catalyst's selectivity. Spectroscopic studies and X-ray analysis confirm that the control arises from the in situ formation of carboxylate-bridged dinuclear complexes, for example, 2 {[MnIII2O(CCl3CO2)2(tmtacn)2]2+} and 3 {[MnII2(OH)(CCl3CO2)2(tmtacn)2]+}, during catalysis. For the first time, the possibility to tune, through the carboxylate ligands employed, both the selectivity and activity of dinuclear Mn-based catalysts is demonstrated. To our knowledge, the system 1/2,6-dichlorobenzoic acid (up to 2000 turnover numbers for cis-cyclooctanediol) is the most active Os-free cis-dihydroxylation catalyst reported to date. Copyright
Mechanistic Links in the in-situ Formation of Dinuclear Manganese Catalysts, H2O2 Disproportionation, and Alkene Oxidation
Angelone, Davide,Abdolahzadeh, Shaghayegh,De Boer, Johannes W.,Browne, Wesley R.
, p. 3532 - 3542 (2015)
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. The in situ formation of catalytically active species through the reduction of a precatalyst, H2O2 disproportionation and alkene oxidation are linked to a common active species.
Microkinetic modeling of cis-cyclooctene oxidation on heterogeneous Mn-tmtacn complexes
Bjorkman, Kathryn R.,Schoenfeldt, Nicholas J.,Notestein, Justin M.,Broadbelt, Linda J.
, p. 17 - 25 (2012)
Experiments and microkinetic modeling were used to investigate the reaction mechanism of cis-cyclooctene oxidation with H2O2 on heterogeneous manganese 1,4,7-trimethyl-1,4,7-triazacyclononane (Mn-tmtacn) catalysts. A mechanism based on literature reports and model discrimination was identified that captured experimental data well, including data at reaction conditions that were not used for parameter estimation. H2O 2 activation on the heterogeneous catalytic complex was identified as the rate-determining step (RDS), and a simple analytical rate expression was derived using the RDS and the pseudo-steady-state approximation for all intermediates. Predicted reaction orders for cis-cyclooctene, water, H 2O2, catalyst, and diol and epoxide products are also consistent with experimental observations and can be rationalized according to the derived rate expression. In addition, the ratio of productive to unproductive H2O2 use is analyzed, and catalyst deactivation is found to be an important step in the reaction mechanism that is highly sensitive to temperature.
Bioinspired nonheme iron complexes derived from an extended series of N,N,O-ligated BAIP ligands
Moelands, Marcel A. H.,Nijsse, Sjoerd,Folkertsma, Emma,De Bruin, Bas,Lutz, Martin,Spek, Anthony L.,Klein Gebbink, Robertus J. M.
, p. 7394 - 7410 (2013)
A series of mononuclear Fe(II) triflate complexes based on the 3,3-bis(1-alkylimidazole-2-yl)propionate ester (BAIP) ligand scaffold are reported. In these complexes, the tripodal N,N,O-BAIP ester ligand is varied by (i) changing the ester moiety (i.e., n-Pr, tert-Bu esters, n-Pr amide), (ii) changing the methylimidazole moieties to methylbenzimidazole moieties, and (iii) changing the methylimidazole moieties to 1-ethyl-4-isopropylimidazole moieties. The general structure of the resulting complexes comprises two facially capping BAIP ligands around a coordinatively saturated octahedral Fe(II) center, with either a transoid or cisoid orientation of the N,N,O-donor manifold that depends on the combined steric and electronic demand of the ligands. In the case of the sterically most encumbered ligand, a four-coordinate all N-coordinate complex is formed as well, which cocrystallizes with the six-coordinate complex. In combination with the catalytic properties of the new complexes in the epoxidation/cis-dihydroxylation of cyclooctene with H2O2, in terms of turnover number and cis-diol formation, these studies provide a number of insights for further ligand design and catalyst development aimed at Fe-mediated cis-dihydroxylation.
OSMIUM TETROXIDE CATALYSED HYDROXYLATION OF HINTERED OLEFINS
Ray, Rahul,Matteson, Donald S.
, p. 449 - 450 (1980)
Osmium tetroxide catalyzed hydroxylation of sterically hindered olefins proceeds efficiently with trimethylamine N-oxide as oxidizing agent in the presents of pyridine.
cis-Dihydroxylation of olefins by a non-heme iron catalyst: A functional model for Rieske dioxygenases
Chen, Kui,Lawrence Jr., Que
, p. 2227 - 2229 (1999)
The first iron complex capable of olefin cis-dihydroxylation in combination with H2O2 provides a functional model for Rieske dioxygenases. Mechanistic studies on the model reaction suggest the participation of an Fe(III)(η2-OOH) intermediate, with the oxygen atoms coming exclusively from H2O2 (see reaction scheme; L denotes a tris(6-methyl-2-pyridylmethyl)amine ligand, Solv = solvent). The similarities between the model and the enzymes strengthen the proposal that an Fe(III)- peroxo intermediate is involved in the enzymatic reactions.
Olefin cis-dihydroxylation versus epoxidation by non-heme iron catalysts: Two faces of an FeIII-OOH coin
Chen, Kui,Costas, Miquel,Kim, Jinheung,Tipton, Adrianne K.,Que Jr., Lawrence
, p. 3026 - 3035 (2002)
The oxygenation of carbon-carbon double bonds by iron enzymes generally results in the formation of epoxides, except in the case of the Rieske dioxygenases, where cis-diols are produced. Herein we report a systematic study of olefin oxidations with H202 catalyzed by a group of non-heme iron complexes, i.e., [FeII(BPMEN)CH3CN)2]2+ (1, BPMEN = N,N′-dimenthyl-N,N′-bis(2-pyridylmethyl)-1,2-diaminoethane) and [FeII(TPA)(CH3CN)2]2+ (4, TPA = tris(2-pyridlymethyl)amine) and their 6- and 5-methyl-substituted derivatives. We demonstrate that olefin epoxidation and cis-dihydroxylation are different facets of the reactivity of a common FeIII-OOH intermediate, whose spin state can be modulated by the electronic and steric properties of the ligand environment. Highly stereoselective epoxidation is favored by catalysts with no more than one 6-methyl substituent, which give rise to low-spin FeIII-OOH species (category A). On the other hand, cis-dihydroxylation is favored by catalysts with more than one 6-methyl substituent, which afford high-spin FeIII-OOH species (category B). For catalysts in category A, both the epoxide and the cis-diol product incorporate 18O from H218O, results that implicate a cis-H18O-Fev=O species derived from O-O bond heterolysis of a cis-H218O-FeIII-OOH intermediate. In contrast, catalysts in category B incorporate both oxygen atoms from H218O2 into the dominant cis-diol product, via a putative FeIII-η2-OOH species. Thus, a key feature of the catalysts in this family is the availability of two cis labile sites, required for peroxide activation. The olefin epoxidation and cis-dihydroxylation studies described here not only corroborate the mechanistic scheme derived from our earlier studies on alkane hydroxylation by this same family of catalysts (Chen, K.; Que, L, Jr. J. Am. Chem. Soc. 2001, 123, 6327) but also further enhance its credibility. Taken together, these reactions demonstrate the catalytic versatility of these complexes and provide a rationale for Nature's choice of ligand environments in biocatalysts that carry out olefin oxidations.
Catalytic epoxidation and 1,2-dihydroxylation of olefins with bispidine-iron(II)/H2O2 systems
Bukowski, Michael R.,Comba, Peter,Lienke, Achim,Limberg, Christian,Lopez De Laorden, Carlos,Mas-Balleste, Ruben,Merz, Michael,Que Jr., Lawrence
, p. 3446 - 3449 (2006)
(Chemical Equation Presented) Going ferryl: FeII complexes with two isomeric bispidine ligands catalyze the oxidation of cyclooctene with H 2O2 in MeCN under aerobic conditions with high selectivity for the epoxide (see scheme; L = bispidine ligand). An {FeIV=O} complex is postulated to be the oxidant, formed by the homolytic cleavage of the O-O bond of an {FeIII-OOH} intermediate. Performing the reaction under argon gives a mixture of cis and trans diols as well as the epoxide.
Bioinspired symmetrical and unsymmetrical diiron complexes for selective oxidation catalysis with hydrogen peroxide
Trehoux, Alexandre,Guillot, Régis,Clemancey, Martin,Blondin, Geneviève,Latour, Jean-Marc,Mahy, Jean-Pierre,Avenier, Frédéric
supporting information, p. 16657 - 16661 (2020/12/18)
Two new symmetrical and unsymmetrical diiron(iii) complexes were synthesized and characterized by X-ray diffraction analysis, mass spectrometry, UV-visible and M?ssbauer spectroscopies. They proved to be good catalysts for alkene and alkane oxidation reactions by H2O2 in acetonitrile solution, and interesting effects of both the nature and the symmetry of the complexes were observed on catalysis in the presence of water.
