Tetraethylammonium-tetrasulfidorhenate

The product can be recrystaUized by first dissolving 2.02 g in 400 mL of MeCN. The dark violet solution is filtered and concentrated to 200 mL. The concentrate is diluted with 200 mL of toluene, and the solution is again concentrated to a volume of 200 mL. Black-green crystals or a purple powder is collected and washed with toluene (50 mL) and Et20 (50 mL). Both forms analyze to be (Et4N)ReS4. The solid is dried in air. Recovery 1.72 g (85%). 

Schafer, W. Kaim, M. Moscherosch, andM. Krejcik, J. Chem. Soc. Chem. Commun., 834 (1992). 

Muller, V. Wittneben, E. Diemann, J. Honnes, and U. Kuetgens, Chem. Pkys. Lett. 225, 359 (1994). 

Submitted by WOLFGANG A. HERRMANN and ROLAND M. KRATZER Checked by JAMES H. ESPENSON and WEH)ONG WANG  

Methyltrioxorhenium(VII) (MTO), CHaReOs, has been shown to be an organo-metallic compound with a broad variety of catalytic properties. Two synthetic pathways have been established the direct alkylation of dirhenium heptoxide (Re207) with tetramethyltin yielding 50% of unreactive trimethylstannyl perrhe-nate, and the alkylation with tributyhnethyltin in the presence of trifluoroacetic anhydride. In the latter case, the formation of the rhenium-containing byproduct can be avoided. The disadvantage of both methods is that the Re207 is extremely moisture-sensitive. 

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