Self‐Assembly of Copper(I) Halide Networks Containing Tetra‐ or Pentameric Ethylcycloarsoxane (C 2 H 5 AsO) n ( m = 4,5) as a flexible Bridging Unit

In complexes of ethylcycloarsoxane (C 2 H 3 AsO) n , the oligomer size n is influenced by the coordinated metal atom. Cyclic tetramers are observed in the porous sheet structures of ∞ 2 [Cu 2 Br 2 {cyclo‐(C 2 H 5 AsO) 4 } 3 ] ( 1 ) and 2 ∞ [Cu 3 I 3 { cyclo‐ (C 2 H 5 As0) 4 ) 2 ] ( 2 ), prepared by the reaction of the appropriate copper(I) halide with (C 2 H 5 AsO) n in acetonitrile. Both complexes contain μ1κ As 1 :2κ As 3 ‐coordinated (C 2 H 5 AsO) 4 ligands as molecular bridging units between individual copper(I) centres leading to large respectively 36‐ and 40‐membered rings. An analogous bridging mode is found in the cyclic oligomers [cyclo‐(ReBr(CO) 3 {μ‐[cyclo‐(C 2 H 5 AsO)}} 4 ]( 3 ) formed by reacting {ReBr(CO) 5 ] with (C 2 H 5 AsO) n in refluxing toluene. – In contrast both [(NH 4 ){ cyclo ‐ (C 2 H 5 AsO) 5 } 2 ][Ag(SCN)] 2 ( 4 ) and 2 ∞[(Cs( cyclo ‐(C 2 H 5 ‐AsO) 3 ] 2 } Cu 2 (μ‐I) I 2 ] ( 5 ) contain pentamers (C 2 H 5 AsO) 5 , which coordinate the NH + 4 and Cs + cations κ 5 O in a pentagonal antiprismatic fashion. In 5 , prepared by self‐assembly from CsI, CuI, and (C 2 H 5 AsO) n in acetonitrile, [Cs[ cyclo ‐{C 2 H 5 AsO} 5 ) 2 ] + sandwich cations are linked thorough μ‐1κ As 1 :2κ As 2 ‐coordinated [Cu 2 l 3 ] − units into polymeric chains. This coordination pattern reflects the unique ring size adaptability of the ambidentate (C 2 J 5 AsO) n ligand.