Catenated (Bi)(n )(n=2, 3, 4) Complexes with Formally Monovalent Bismuth Centres

The reduction of Bi(III) and Bi(II) compounds supported by the NONR-ligand (NONR=[O(SiMe2NR)2]2−; R=Dipp=2,6-iPr2C6H3, tBu) afforded species in which the metal was present in a range of formal oxidation-states. Cyclic voltammetry performed on the Bi(II) radical [Bi(NONDipp)]⋅ indicated that the Bi(I) oxidation state was accessible, although the lifetime of the resultant species was short. Preparative scale reactions of Bi(NONDipp)Cl and excess LiBEt3H afforded the tetrametallic cluster Bi4(NONDipp)2, in which the bismuth atoms form a [1,2]-edge missing tetrahedron. Reduction of the dibismuthane [Bi(NONtBu)]2 with potassium in the presence of [2.2.2]-cryptand generated a tribismuthinide salt containing the [{Bi(NONtBu)}2(μ-Bi)]− anion and a non-coordinating [K([2.2.2]-crypt)]+ cation. Reduction of isolated [Bi(NONDipp)]⋅ with the Mg(I) reagent [Mg(BDIDipp)]2 (BDIDipp=[HC{C(Me)NDipp}2]−) formed the dibismuthene [Bi(μ-NONDipp)Mg(BDIDipp)(THF)]2, with a crystallographically verified Bi=Bi multiple bond.