Redox and Coordination Behavior of the Hexaphosphabenzene Ligand in [(Cp∗Mo)2(μ,η6:η6-P6)] Towards the "naked" Cations Cu+, Ag+, and Tl+

Abstract

Although the cyclo-P6 complex [(Cp∗Mo)2(μ,η6:η6-P6)] (1) was reported 30 years ago, little is known about its chemistry. Herein, we report a high-yielding synthesis of 1, the complex 2, which contains an unprecedented cyclo-P10 ligand, and the reactivity of 1 towards the "naked" cations Cu+, Ag+, and Tl+. Besides the formation of the single oxidation products 3 a,b which have a bisallylic distorted cyclo-P6 middle deck, the [M(1)2]+ complexes are described which show distorted square-planar (M=Cu(4 a), Ag(4 b)) or distorted tetrahedral coordinated (M=Cu(5)) M+ cations. The choice of solvent enabled control over the reaction outcome for Cu+, as proved by powder XRD and supported by DFT calculations. The reaction with Tl+ affords a layered two-dimensional coordination network in the solid state. One ring to bind them all! The reactivity of the long-known hexaphosphabenzene complex 1 has been studied for the first time. The coordination of 1 to Cu+, Ag+, and Tl+ affords layered compounds as supramolecular analogues of graphene, while oxidation leads to a bisallylic distortion of the P6 ring. A cyclo-P10 complex 2 was also characterized, which is the largest known cyclic polyphosphorus complex.