Polymeric two- and three-dimensional transition-metal networks. Crystal structures and magnetic properties

A strategy for the design of molecule-based magnets consists of assembling transition-metal ions in two-dimensional (2D) or three-dimensional (3D) networks in order to maximize the interactions between the magnetic centers. While increasing the dimensionality of the compounds, an increase in T-C the critical temperature of spontaneous magnetization should, in principal, be favoured. We are currently studying materials that are formed by the interaction of transition-metal ions with the oxalate ligand, C2O42-, and will present a straightforward concept for building up achiral 2D and chiral 3D homo- and bimetallic networks. Whereas a variety of metal ions can be incorporated, a correlation of the magnetic behavior and the relationship to the special topology of e.g. the chiral, cubic 3-connected 10-gon net (10,3) is not yet fully understood.