Researchers in Germany have made a unique iron complex, based on ferrocene sandwiches, which could shed new light on transition-metal catalysts. 

Matthias Wagner and colleagues at J W Goether University have made a pentanuclear iron(II) cluster, which is the first example of a ferra[1]ferrocenophane. The core of the cluster is a complex in which the two cyclopentadienyl ligands of a ferrocene are bridged by an iron(II) ion. Two such ferra[1]ferrocenophanes are linked by a ferrocenediyl unit. 

Wagner plans to investigate the potential interactions between the two non-ferrocene iron ions and between the non-ferrocene and the ferrocene iron centres in more detail. 'It will contribute to a deeper understanding of the electronic properties of transition metal complexes featuring ferrocene-based ligands which are of great interest in homogeneous catalysis,' he said. 

Ian Manners, chair of inorganic, macromolecular and materials chemistry at the University of Bristol, UK, said the compound is 'a unique and very interesting new example - a type of ferrocenophane with an iron atom in the bridge which forms part of a remarkable pentanuclear iron complex.' 

Wagner plans to use different transition metal ions to create other similar structures. This should allow clusters to be created with a wide range of electronic and magnetic properties, he said. 

Nicola Burton