Coordination Chemistry of Copper and Nickel with Xenon Difluoride and the Hexafluororuthenate(V) Anion: Synthesis and Structural Studies

M(RuF₆)₂ (M = Cu, Ni) are synthesized from MF₂, F₂, and Ru under UV light. Different amounts of XeF₂ are added to the salt. In the reactions between M(RuF₆)₂ and 2XeF₂, the compounds [M(XeF₂)₂](RuF₆)₂ (M = Cu, Ni) are formed. Their crystal structures are isotypic. However, when reacted with an excess of XeF₂, the compounds [M(XeF₂)₆](RuF₆)₂ (M = Cu, Ni) are obtained.

In the photochemical reactions between MF₂ (M = Cu, Ni), Ru, and F₂ in anhydrous HF, Cu(RuF₆)₂, and Ni(RuF₆)₂ are formed. Only crystals of Cu(RuF₆)₂ are obtained during the crystallization of the powdered products. Cu(RuF₆)₂ crystallizes in the triclinic space group P1¯$\bar{1}$. The Cu atoms are coordinated by six F atoms, which are shared with octahedral RuF₆ units. Together, they form slabs that are interconnected by van der Waals forces. In the reactions between M(RuF₆)₂ (M = Cu, Ni) and 2XeF₂ (1:2 molar ratio), [Cu(XeF₂)₂](RuF₆)₂ and [Ni(XeF₂)₂](RuF₆)₂ are formed. They both crystallize in the monoclinic space group P2₁/c. The metal center is coordinated by six F atoms. Two F atoms are provided by two nonbridging XeF₂ molecules, while the remaining four originate from four bridging [RuF₆]^- anions. In the reactions between M(RuF₆)₂ (M = Cu, Ni) and an excess of XeF₂, [Cu(XeF₂)₆](RuF₆)₂ and [Ni(XeF₂)₆](RuF₆)₂ are formed. They are not isostructural, as the first crystallizes in the triclinic space group P1¯$\bar{1}$, while the second crystallizes in the trigonal space group R3¯$\bar{3}$. In both cases, homoleptic cations [M(XeF₂)₆]²⁺ are present, with the metal center coordinated by six nonbridging XeF₂ molecules, while the [RuF₆]^- anions are discrete.