Methylrhenium trioxide

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Methylrhenium trioxide
Methylrhenium-trioxide-3D-balls.png
Identifiers
CAS number 70197-13-6 YesY
ChemSpider 10621726
Jmol-3D images Image 1
Properties
Molecular formula CH3ReO3
Molar mass 249.24 g/mol
Appearance white powder
Melting point 112 °C (385 K)
Solubility in water highly soluble in water
Hazards
MSDS External MSDS
S-phrases S22, S23, S24/25
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Methylrhenium trioxide, also known as methyltrioxorhenium, is an organometallic compound with the formula CH3ReO3. It is a volatile, colourless solid that has been used as a catalyst in some laboratory experiments. In this compound, Re has a tetrahedral coordination geometry with one methyl and three oxo ligands. The oxidation state of rhenium is +7.

Synthesis[edit]

Methylrhenium trioxide is commercially available. It can be prepared by many routes, a typical method is the reaction of Re2O7 and tetramethyltin:[1]

Re2O7 + (CH3)4Sn → CH3ReO3 + (CH3)3SnOReO3

Analogous alkyl and aryl derivatives are known. Compounds of the type RReO3 are Lewis acids, forming both 1:1 and 1:2 adducts with halides and amines.

Uses[edit]

Methylrhenium trioxide serves as a heterogeneous catalyst for a variety of transformations. Supported on Al2O3/SiO2, it catalyzes olefin metathesis at 25 °C.

In solution, MTO catalyses for the oxidations with hydrogen peroxide. Terminal alkynes yield the corresponding acid or ester, internal alkynes yield diketones, and alkenes give epoxides. MTO also catalyses the conversion of aldehydes and diazoalkanes into an alkene.[2]

References[edit]

  1. ^ Herrmann, W. A.; Kratzer R. M.; Fischer R. W. (1997). "Alkylrhenium Oxides from Perrhenates: A New, Economical Access to Organometallic Oxide Catalysts". Angew. Chem. Int. Ed. Engl. 36 (23): 2652–2654. doi:10.1002/anie.199726521. 
  2. ^ Hudson, A. “Methyltrioxorhenium” Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons: New York, 2002.