Thioether-Coordinated Nickel Oxidation States. A NiIIIS2N4 Family Incorporating Hexadentate Thioether−Azo−Oxime Chelation

The isolation of the first family of thioether-coordinated nickel(III) complexes, [Ni(RxL)]PF6, incorporating acyclic ligands has been achieved using thioether−azo−oximes of the type HONC(R)NNC6H4S(CH2)xSC6H4NNC(R)NOH (H2RxL, x = 2, 3; R = Ph, α-naphthyl). The synthesis consists of electrooxidation of NiII(RxL) precursors having proven NiS2N4 coordination spheres. The [Ni(RxL)]+ species have a dz2 ground state and display azo-14N superhyperfine EPR splitting. The nickel(III) state is stabilized well, the nickel(III)−nickel(II) reduction potential being relatively low.