The redox chemistry of [Cp*Fe(η -As )] (1, Cp*=η -C Me ) has been investigated by cyclic voltammetry, revealing a redox behavior similar to that of its lighter congener [Cp*Fe(η -P )]. However, the subsequent chemical reduction of 1 by KH led to the formation of a mixture of novel As scaffolds with n up to 18 that are stabilized only by [Cp*Fe] fragments. These include the arsenic-poor triple-decker complex [K(dme) ][{Cp*Fe(μ,η -As )} ] (2) and the arsenic-rich complexes [K(dme) ] [(Cp*Fe) (μ,η -As )] (3), [K(dme) ] [(Cp*Fe) (μ,η -As )] (4), and [K(dme) ] [(Cp*Fe) (μ ,η -As )] (5). Compound 4 and the polyarsenide complex 5 are the largest anionic As ligand complexes reported thus far. Complexes 2-5 were characterized by single-crystal X-ray diffraction, H NMR spectroscopy, EPR spectroscopy (2), and mass spectrometry. Furthermore, DFT calculations showed that the intermediate [Cp*Fe(η -As )] , which is presumably formed first, undergoes fast dimerization to the dianion [(Cp*Fe) (μ,η -As )] .

Die Untersuchung der Redoxchemie von [Cp*Fe(h 5 -As 5 )] (1)( Cp* = h 5 -C 5 Me 5 )m ittels Cyclovoltammetrie ergab ein Redoxverhalten, das jenem des leichteren Verwandten [Cp*Fe(h 5 -P 5 )] ähnelt. Die anschließende chemische Reduktion von 1 durch KH führt zur Bildung eines Gemisches von Produkten mit neuartigen As n -Gerüsten (n = bis zu 18), die lediglich durch[ Cp*Fe]-Fragmente stabilisiert werden. Dazu gehçren der Arsen-arme Tripeldeckerkomplex [K(dme) 2 ]-[{Cp*Fe(m,h 2:2 -As 2 )} 2 ]( 2)u nd die Arsen-reichen Komplexe [K(dme) 3 ] 2 [(Cp*Fe) 2 (m,h 4:4 -As 10