A self-assembled 2D molecule-based magnet: the honeycomb layered material [Co3Cl4(H2O)2[Co(Hbbiz)3]2]

TL;DR: The most effective bridging groups with respect to magnetic exchange interactions are cyanide, dicyanamide, and oxalate as mentioned in this paper, which can mediate sufficiently strong magnetic interactions between metal ions such that bulk magnetic ordering can occur.

Abstract: Research in the area of molecule-based magnets is rapidly expanding, owing, in part, to numerous breakthroughs in the past decade.[1] The preparation of solid-state architectures of varying dimensionalities from specifically tailored paramagnetic building blocks has proven to be very successful, and also clearly multidisciplinary. Materials science and supramolecular chemistry efforts have joined forces with classical organic and inorganic chemistry in the design of solid-state materials whose magnetic properties rival, and sometimes even exceed, those of classic inorganic solids.[2] The moleculebased strategy allows for the preparation of unusual materials that cannot otherwise be obtained, for example, materials that combine two or more physical properties in the same compound[3] or molecules with magnetic bistability.[4] The solid-state structures of the majority of molecule-based magnetic materials consist of extended networks of paramagnetic metal ions held in close proximity by bridging ligands that allow for magnetic exchange. The dimensionality of the system dictates the overall magnetic properties and can be controlled by the use of capping ligands[5] or templating counterions.[6] Unfortunately, few ligands are capable of mediating sufficiently strong magnetic interactions between metal ions such that bulk magnetic ordering can occur. Apart from monoatomic ligands (such as oxide or halide bridges), the most effective bridging groups with respect to magnetic exchange interactions are cyanide,[7] dicyanamide,[8] and oxalate.[9] Common features of these ligands are that they contain only a small number of atoms, and that they offer a p as well as a s pathway for magnetic superexchange interactions. Organic radicals have also been successfully applied