| Abstract: | Preparation and Structure of Tetraethylcyclotetraarsoxane Complexes of Copper(I) Halides The polymeric complexes Cu4Cl4{cyclo-(C2H5AsO)4}3]n ( 1 ), Cu3Br3{cyclo-(C2H5AsO)4}2]n ( 2 ) and Cu6I6{cyclo-(C2H5AsO)4}3]n ( 3 ) were prepared by the reaction of (C2H5AsO)n and CuX (X = Cl, Br, I) in acetonitrile and characterised by X-ray analysis. All three complexes contain only tetramers (C2H5AsO)4 as ligands, in which the As4O4 ring systems coordinate between two and four Cu-atoms. In each case one As4O4 ring with a crown-shaped conformation is observed, which coordinates either four (in 1 ) or three (in 2 and 3 ) axially sited Cu-atoms. In addition there are further (C2H5AsO)4 ligands, which display either a boat-chair- (in 1 ) or a twist-chair-conformation (in 1–3 ). The individual building units are connected to one another via Cu? X? Cu bridges (in 2 and 3 ) and/or centrosymmetric As4O4 ring systems (in 1–3 ) into chain ( 1 ) or layer structures ( 2 und 3 ). |
