Methylrhenium trioxide

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. This chemical substance adopts a tetrahedral molecular geometry with rhenium surrounded by one methyl and three oxo ligands. The oxidation state of rhenium is +7.

Methylrhenium trioxide

Names
IUPAC name Methyl(trioxo)rhenium(VII)
Other names Methyltrioxorhenium(VII)
Identifiers
CAS Number	70197-13-6 Y
3D model (JSmol)	Interactive image
Abbreviations	MTO
ChemSpider	10621726 N
ECHA InfoCard	100.202.821
EC Number	677-701-9
PubChem CID	2734010
UNII	883D8RDD5Q
CompTox Dashboard (EPA)	DTXSID40370077
InChI InChI=1S/CH3.3O.Re/h1H3;;;; N Key: PQTLALPZRPFYIT-UHFFFAOYSA-N 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). N verify (what is YN ?) Infobox references

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]