ReF 7 and ReOF 5 as fluoride ion donors

Abstract

Salts containing the ReF 6 + ion have been prepared by one-electron oxidation of ReF 6 using KrF + salts. The compounds ReF 6 +MF 6 − (M = Au, Sb) are of moderate stability, tending to decompose to ReF 7 and the corresponding pentafluoride. This gives rise to isolated ReF 7 and MF 5 molecules within the ionic lattice, whose presence is demonstrated by Raman spectroscopy. Interaction of ReF 6 and PtF 6 produced not the salt ReF 6 +PtF 6 − (1), but rather the deep red (PtF 5) 4 when PtF 6 was present in excess, and PtF 4 when ReF 6 was in excess. ReF 6 and IrF 6 appear to be in equilibrium with ReF 7 and (IrF 5) 4, possibly via an ionic intermediate ReF 6 +(IrF 6·xIrF 5) −. The salts ReOF 4 +MF 6− (M = As, Au, Sb) have been characterized. In contrast to the behaviour of IOF 5 and IF 7, ReOF 5 is a better fluoride ion donor than ReF 7.