Reaction of osmium tetroxide with alkenes, glycols, and alkynes; oxo-osmium(VI) esters and their structures

Abstract

Osmium tetroxide reacts with mono-alkenes (R) to give five-co-ordinate mono- or di-esters of the saturated diolato-ligand (O₂R)^2–, viz. [Os₂O₄(O₂R)₂](I) and [OsO(O₂R)₂](II); (II) may also be obtained by the reaction of OsO₄ with the glycol R(OH)₂. With alkenes (R) or acetylene in the presence of tertiary nitrogen bases, L, the octahedral ‘osmyl’ species [OsO₂L₂(O₂R)](III) and [Os₂O₄L₄(O₄C₂H₂)](IV) are formed. Spectroscopic and other data are used to assign structures to these complexes; ¹⁸O and ²H substitution has been used to help the interpretation of i.r. data.