Rhenium Trioxide MTO

Preparation of methyltechnetium trioxide 2 by a similar procedure was reported soon after.8 This approach has the disadvantage of creating a full 

Re—O Bond Lengths, O—Re-O Bond Angles, and Re=Q Infrared Stretching 

An important practical consideration is the choice of the anhydride trifluoroacetic anhydride is quite readily available, but the byproduct tri-methyltin trifluoroacetate is approximately as volatile as MTO, and the usual purification (sublimation) can be quite difficult. However, use of perfluoroglutaric anhydride results in a relatively nonvolatile tin perfluoro-glutarate, allowing for a straightforward isolation of MTO. 

MTO is an off-white crystalline solid which is stable to the ambient atmosphere. It is soluble in common organic solvents and in water, although it decomposes in water at high pH to form methane10 (see later discussion). It is easily sublimed and should be stored in a sealed container. It is reported to have a high photoreactivity in aqueous solutions.11 

A substantial portion of the early interest in MTO pertained to its use in alkene metathesis.12 Of more relevance to oxidation processes, much work has also involved examining Lewis base adducts of this electrophilic, (formally) 14-electron complex. Generally, nitrogen bases coordinate trans to the methyl group. Bidentate ligands such as bipyridyl lead to the fac-Me(N N)Re03 isomer of the octahedral complex. Table I summarizes some of the structural information from X-ray crystallographic and infrared studies. 

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