Methylrhenium trioxide

Methylrhenium trioxide
Names
	Other names methyltrioxorhenium
Identifiers
CAS Number	70197-13-6 ;
3D model (JSmol)	Interactive image;
ChemSpider	10621726 ;
ECHA InfoCard	100.202.821
PubChem CID	2734010;
UNII	883D8RDD5Q;
CompTox Dashboard (EPA)	DTXSID40370077 ;
	InChI InChI=1S/CH3.3O.Re/h1H3;;;; Key: PQTLALPZRPFYIT-UHFFFAOYSA-N ; InChI=1/CH3.3O.Re/h1H3;;;;/rCH3O3Re/c1-5(2,3)4/h1H3 Key: PQTLALPZRPFYIT-YHFCCQKIAF;
	SMILES C[Re](=O)(=O)=O;
Properties
Chemical formula	CH3ReO3
Molar mass	249.24 g/mol
Appearance	white powder
Melting point	112 °C (234 °F; 385 K)
Solubility in water	highly soluble in water
Hazards
Safety data sheet	External MSDS
GHS pictograms
GHS Signal word	Warning
GHS hazard statements	H272, H315, H319, H335, H413
GHS precautionary statements	P210, P220, P221, P261, P264, P271, P273, P280, P302+352, P304+340, P305+351+338, P312, P321, P332+313, P337+313, P362, P370+378, P403+233, P405, P501
	Except where otherwise noted, 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

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

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] and the oxidation of amines to N-oxides with sodium percarbonate.[3]

References

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.
Hudson, A. “Methyltrioxorhenium” Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons: New York, 2002.
Jain, Suman L.; Joseph, Jomy K.; Sain, Bir (2006). "Rhenium-Catalyzed Highly Efficient Oxidations of Tertiary Nitrogen Compounds to N-Oxides Using Sodium Percarbonate as Oxygen Source". Synlett: 2661–2663. doi:10.1055/s-2006-951487.

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[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.

[3] Jain, Suman L.; Joseph, Jomy K.; Sain, Bir (2006). "Rhenium-Catalyzed Highly Efficient Oxidations of Tertiary Nitrogen Compounds to N-Oxides Using Sodium Percarbonate as Oxygen Source". Synlett: 2661–2663. doi:10.1055/s-2006-951487.