Methylrhenium trioxide

Methylrhenium trioxide
Names
	Other names methyltrioxorhenium(VII)
Identifiers
CAS Number	70197-13-6 ;
3D model (JSmol)	Interactive image;
Abbreviations	MTO
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	249.239 g·mol−1
Appearance	white powder
Melting point	112 °C (234 °F; 385 K)
Solubility in water	highly soluble in water
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H272, H315, H319, H335, H413
Precautionary statements	P210, P220, P221, P261, P264, P271, P273, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P370+P378, P403+P233, P405, P501
Safety data sheet (SDS)	External MSDS
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Methylrhenium trioxide, also known as methyltrioxorhenium(VII), is an organometallic compound with the formula CH₃−ReO₃. It is a volatile, colourless solid that has been used as a catalyst in some laboratory experiments. In this compound, rhenium 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 rhenium heptoxide and tetramethyltin:[1]

Re₂O₇ + (CH₃)₄Sn → CH₃ReO₃ + (CH₃)₃Sn−O−ReO₃

Analogous alkyl and aryl derivatives are known. Compounds of the type R−ReO₃ 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 alumina/silica, it catalyzes olefin metathesis at 25 °C.

In solution, methylrhenium trioxide catalyses for the oxidations with hydrogen peroxide. Terminal alkynes yield the corresponding carboxylic acid or ester, internal alkynes yield diketones, and alkenes give epoxides. Methylrhenium trioxide 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.