Multiple Bonds Between Main‐Group Elements and Transition Metals, CLXIV. Alkylrhenium(VI) Oxides‐Synthesis and Characterization

Most alkylrhenium(VII) oxides, e.g. (( cyclo )‐C 3 H 5 )Re0 3 ( 2 ) are rather sensitive to temperature and moisture with the prominent exception of methyltrioxorhenium ( 1 ). The corresponding alkylrhenium(VI) oxides of formula [RR′(O)‐ Re( μ ‐O)] 2 [RR′( cyclo )‐C 3 H 5 ( 3 ), i Pr ( 4 ); RCH 3 , R′C 2 H 5 ( 5 ), RCH 3 , R′ i Pr ( 6 )] are much more stable in this regard. They can be handled in air at room temperature. They were synthesized from Re 2 0 7 and dialkylzinc precursors, fully characterized and are available in much higher yields than their Re VII congeners. Mixed tetraalkyltetraoxodirhenium(VI) complexes (R # R′) synthesized from 1 and dialkylzinc compounds form as a mixture of cis / trans isomers. They are oily liquids at room temperature. The ReO and Re‐Re stretching force constants as a measure of the bond strengths, were determined from IR and Raman data.