Cover Picture

Abstract

The cover picture shows a perspective view of an octanuclear NiII complex with the quadridentate ligand threo-1,2,3,4-tetraaminobutane (red: NiII, blue: N, H omitted). The eight NiII centers, which form the vertices of a slightly disordered cube, have alternate Λ and Δ configurations. The twelve chiral ligand molecules are located at the edges of this cube and generate an [Ni8L12]16+ cage of idealized T symmetry. The cuboidal structure has a rather large and highly chiral cavity of about 12 Å in diameter. The bis-bidentate coordination mode of the tetraamine ligand has also been observed in a series of polynuclear CuII solid-state structures, exhibiting infinite two- and three-dimensional porous networks, helices, and ring structures. This ligand has considerable potential as a building block for chiral coordination polymers. The solid-state structures together with a comprehensive solution study of these complexes are described in detail by K. Hegetschweiler et al. on p. 917 ff.