Rhenium carbonyl fluorides: preparation, crystal structure, and some properties of hexacarbonylrhenium(I)µ-fluoro-bis[pentafluororhenate(V)]

Abstract

The title compound [Re^I(CO)₆][Re^V₂F₁₁] has been prepared as green (α) and yellow (β) crystalline modifications by the reaction of ReF₆ with [Re₂(CO)₁₀] in anhydrous hydrogen fluoride at room temperature. Some physical properties have been examined. Crystals of the α form are orthorhombic, space group Pnma, with unit-ceil dimensions a= 15.30(9), b= 13.64(7), c= 8.16(3)Å, and Z= 4. The structure has been refined by three-dimensional least-squares methods to R 0.064 for 748 reflections measured by diffractometer. The compound contains discrete [Re(CO)₆]⁺ and [Re₂F₁₁]^– ions. The cation is closely octahedral, and the anion contains a single linear fluorine bridge linking two eclipsed ReF₆ octahedra.