Rhenium carbonyl fluorides: preparation of [Re(CO)6][ReF6] and some reactions of [Re(CO)5F·ReF5]

Abstract

The compound [Re(CO)₆][ReF₆] has been prepared by the reaction of [Re(CO)₅F·ReF₅] with carbon monoxide in anhydrous hydrogen fluoride. It is also formed in the fluorination of [Re₂(CO)₁₀] by xenon difluoride in Genetron 113 (1,1,2-trichloro-1,2,2-trifluoroethane) as solvent if carbon monoxide released in the reaction is allowed to accumulate in the system. The compound [Re(CO)₅F·ReF₅] undergoes ligand-substitution reactions in anhydrous hydrogen fluoride to give products containing [Re(CO)₅L]⁺ ions (L = PF₃ or CH₃CN). No permanent reaction was observed with L = SO₂. When β-[Re(CO)₆][Re₂F₁₁] is treated with carbon monoxide in anhydrous hydrogen fluoride it is slowly converted into a new crystal modification, γ-[Re(CO)₆][Re₂F₁₁], and a small amount of [Re(CO)₆][ReF₆] is also formed.