New [Ru(NH3)6]MF6 phases: precursors to catalysts for halogenation reactions

A series of hexamminoruthenium(III)–hexafluorometallates of the type [Ru(NH3)6]MF6 (M = Al, Ga, In, Sc, V, Cr, Fe) were synthesized for the first time from the aqueous solutions of the corresponding salts. All these compounds crystallize in a cubic structure (space group Pa3). The structure consists of [Ru(NH3)6]3+ and [MF6]3− octahedral units arranged in a rocksalt-type lattice and are fixed in the lattice by weak hydrogen bonds. Thermogravimetric studies showed that the phases undergo in situ reduction at 280–300°C in inert atmosphere to form homogeneously dispersed Ru(0) and metal fluorides. Depending on the decomposition conditions and M cation various forms of metal fluorides can be stabilized. It has been demonstrated that hexammineruthenium (III) hexafluorometallates are ideal precursors for preparing Ru(0) supported on metal fluoride catalysts for processing various halogented hydrocarbons through hydrogenation and fluorination chemistries.