Isolation and Characterization of the Homoleptic Nickel(I) and Nickel(II) Bis-benzene Sandwich Cations

A stable salt of the metalloradical [Ni(C6H6)(2)](+) hitherto unknown in the condensed phase was synthesized from [Ni(CO)(4)](+)[WCA](-) and benzene ([WCA](-)=[F{Al(ORF)(3)}(2)](-); R-F=C(CF3)(3)). Single crystal XRD reveals a remarkable asymmetrically eta(3),eta(6)-slipped sandwich structure. The magnetic properties of the [Ni(C6H6)(2)](+) cation were determined in solution and in the gas phase. Oxidation with the synergistic Ag+/0.5 l(2) system led to the salt [Ni(C6H6)(2)](2+)([WCA](-))(2). All products were fully characterized by means of IR, Raman, NMR/EPR, single crystal and powder XRD.

Automated summary

A stable salt of the metalloradical [Ni(C6H6)(2)](+) previously unknown in the condensed phase was synthesized and fully characterized. It exhibits a remarkable asymmetrically eta(3),eta(6)-slipped sandwich structure.