CuX (X = Br, I) Oligomers and Polymerie Chains in Tetramethylcyclotetra- arsoxane-Bridged Networks [CunXn{cyclo-(CH3AsO)4}2] (n = 4, 6, 8)

Abstract

Open lamellar structures 2∞[Cu4I4{cyclo-(CH3AsO)4}2] (1) and 2∞[{CuX(CuX · CH3CN)2}{cyclo-(CH3AsO)4}] [X = Br (2), X =I (3)] may be prepared by self-assembly from CuX and methylcycloarsoxane (CH3AsO)n in acetonitrile solution at 100- 130 °C. Whereas 1 contains CU4I4 oligomers consisting of three fused (Cul)2 rings, 2 and 3 exhibit infinite 1∞[CuX] single chains. An acceleration in the rate of heating between 20 and 100 °C from 2 °C h-1 to 5 °C h-1 for CuBr:As = 2:1 allows the isolation of the chain structure 1∞[{(CuBr)2(CuBr · CH3CN)2{cyclo-(CH3AsO)4}] (4), as an intermediate product on the reaction pathway to 2. Compound 4 contains cage-like [Cu4Br3(AsO)4] units in which the Cu and Br atoms belong to a 1∞[Cu2Br2] double chain containing fused (CuBr)3 six-membered rings.