Oxoaryls of rhenium-(V) and -(VI) and osmium(VI). X-Ray crystal structures of dimesityldioxorhenium(VI), tetramesityloxorhenium(VI), and dimesityldioxoosmium(VI)

Abstract

The interaction of mesitylmagnesium bromide with [Me₃NH][ReO₄] or Re₂O₇ leads to the isolation of the diamagnetic rhenium(V) complex [(mes)₂ReO₂]₂Mg(thf)₂(mes = mesityl, thf = tetra-hydrofuran), which can be oxidized to the paramagnetic compound ReO₂(mes)₂; ReOCl₄ gives, instead, the paramagnetic rhenium(V) complex ReO(mes)₄ along with minor amounts of ReO₂(mes)₂, upon oxidation of the reaction solutions. All three rhenium starting materials with O-tolylmagnesium bromide or o-methoxyphenylmagnesium bromide lead similarly to the paramagnetic complexes ReO(o-MeC₆H₄)₄ and ReO(o-MeOC₆H₄)₄, respectively. The diamagnetic compound OsO₂(mes)₂ has also been prepared by oxidizing solutions from the interaction of osmium tetraoxide with the appropriate Grignard reagent. The X-ray crystal structures of ReO₂(mes)₂, OsO₂(mes)₂, and ReO(mes)₄ have been determined to reveal tetrahedral, tetrahedral, and tetragonal pyramidal geometries respectively.