Mononuclear Organomolybdenum(VI) Dioxo Complexes:  Synthesis, Reactivity, and Catalytic Applications

Kühn, Fritz E.; Santos, and Ana M.; Abrantes, Marta

doi:10.1021/cr040703p

Cited by 220 publications

(86 citation statements)

References 89 publications

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“…These results can be regarded as acceptable, particularly when compared with other epoxidation catalysts based either on rhenium or other transition metals. [3,22,23] …”

Section: O Nmr Spectroscopymentioning

confidence: 99%

MTO Schiff‐Base Complexes: Synthesis, Structures and Catalytic Applications in Olefin Epoxidation

Zhou

Zhao

Jun

et al. 2006

Chemistry A European J

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Several Schiff‐base ligands readily form complexes with methyltrioxorhenium(VII) (MTO) by undergoing a hydrogen transfer from a ligand‐bound OH group to a ligand N atom. The resulting complexes are stable at room temperature and can be handled and stored in air without problems. Due to the steric demands of the ligands they display distorted trigonal‐bipyramidal structures in the solid state, as shown by X‐ray crystallography, with the O− moiety binding to the Lewis acidic Re atom and the Re‐bound methyl group being located either in cis or trans position to the Schiff base. In solution, however, the steric differences seem not to be maintained, as can be deduced from 17O NMR spectroscopy. Furthermore, the Schiff‐base ligands exchange with donor ligands. Nevertheless, the catalytic behaviour is influenced significantly by the Schiff bases coordinated to the MTO moiety, which lead either to high selectivities and good activities or to catalyst decomposition. A large excess of ligand, in contrast to the observations with aromatic N‐donor ligands, is detrimental to the catalytic performance as it leads to catalyst decomposition.

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“…These results can be regarded as acceptable, particularly when compared with other epoxidation catalysts based either on rhenium or other transition metals. [3,22,23] …”

Section: O Nmr Spectroscopymentioning

confidence: 99%

MTO Schiff‐Base Complexes: Synthesis, Structures and Catalytic Applications in Olefin Epoxidation

Zhou

Zhao

Jun

et al. 2006

Chemistry A European J

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“…It is chemically robust [1] and shows little propensity to participate in the myriad reactions that are characteristic of its Group 6 transition-metal analogues, [MO 2 ] 2+ . [2][3][4][5][6] Furthermore, this stability coupled with its mobility in the aqueous phase means that it is a problematic environmental contaminant. [7][8][9] A better understanding of the reduction of the mobile uranyl ion to insoluble U IV phases, through the pentavalent [UO 2 ] + ion, is important in the context of environmental immobilization and the treatment of mixed waste.…”

Section: Introductionmentioning

confidence: 99%

The Effect of the Equatorial Environment on Oxo‐Group Silylation of the Uranyl Dication: A Computational Study

Yahia

Arnold

Love

et al. 2010

Chemistry A European J

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We thank the Insitut Universitaire de France, CALMIP, CCRT, and CINES for their grant of computing time; CNRS, UPS, and CEA for financial support of this work; and the EPSRC and the University of Edinburgh for funding. Supporting information:Supporting information for this article is available online at http://dx.doi.org/10.1002/chem.200902991 Cartesian coordinates of the optimised structures are included. Keywords:density functional calculations;equatorial ligands;macrocycles;silylation;uranium Synopsis:A DFT study of the silylation of the U-O bond in a macrocyclic uranyl complex demonstrates the importance of the presence, but not the identity, of the equatorial ligands upon the silylation of the uranyl U-O bond, and the influence of the oxo-potassium interaction at the opposing oxo group. Page 1 of 21 AbstractA theoretical investigation of the reductive oxo-group silylation reaction of the uranyl dication held in a Pacman macrocylic environment has been carried out. The effect of the modeling of the Pacman ligand on the reaction profiles is found to be important, with the dipotassiation of a single oxo group identified as a key component in promoting the reaction between the SiX and uranium-oxo bonds. This reductive silylation reaction is also proposed to occur in an aqueous environment but was found not to operate on bare ions; in this latter case, substitution of a ligand in the equatorial plane was the most likely reaction. These results demonstrate the importance of the presence but not the identity of the equatorial ligands upon the silylation of the uranyl UO bond.

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“…High-valent molybdenum oxo compounds are of great importance as catalysts for oxygen atom transfer (OAT) reactions, both in nature as well as in industrial processes [1][2][3][4]. The first clear indication of molybdenum-mediated oxo transfer was the catalytic aerial oxidation of tertiary phosphines in the presence of the dithiocarbamate complex, Mo VI O 2 (S 2 CNEt) 2 [5,6].…”

Section: Introductionmentioning

confidence: 99%

Effect of an Ionic Liquid on the Catalytic Performance of Thiocyanatodioxomolybdenum(VI) Complexes for the Oxidation of Cyclooctene and Benzyl Alcohol

et al. 2009

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The complexes (PPh 4 ) 2 [Mo VI O 2 (NCS) 4 ] (1), Mo VI O 2 (NCS) 2 (di-tBu-bipy) (2) and Mo 2 VI O 5 (NCS) 2 (di-t Bu-bipy) 2 (3) (di-tBu-bipy = 4,4 0 -di-tert-butyl-2,2 0 -bipyridine) were studied as catalyst precursors for the oxidation of cyclooctene (Cy8) and benzyl alcohol (BzOH), using either dimethyl sulfoxide (DMSO) or tert-butyl hydroperoxide (TBHP) as oxidant. By dissolving complex 2 in the room temperature ionic liquid 1-butyl-3-methylpyridinium tetrafluoroborate, the catalytic performance with TBHP was improved (higher selectivity to the aldehyde and higher Cy8 conversions). For Cy8 oxidation, the unreacted substrate and products were easily extracted with n-hexane, and the ionic phase containing the catalyst could be reused without loss of catalytic performance.

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Mononuclear Organomolybdenum(VI) Dioxo Complexes: Synthesis, Reactivity, and Catalytic Applications

Cited by 220 publications

References 89 publications

MTO Schiff‐Base Complexes: Synthesis, Structures and Catalytic Applications in Olefin Epoxidation

MTO Schiff‐Base Complexes: Synthesis, Structures and Catalytic Applications in Olefin Epoxidation

The Effect of the Equatorial Environment on Oxo‐Group Silylation of the Uranyl Dication: A Computational Study

Effect of an Ionic Liquid on the Catalytic Performance of Thiocyanatodioxomolybdenum(VI) Complexes for the Oxidation of Cyclooctene and Benzyl Alcohol

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