Molecular clusters that can bind an unusually high number of ferrocene units may extend the range of applications for these multi-tasking molecules. 

Viswanathan Baskar and Peter Roesky from the Freie Universität Berlin, Germany, have synthesised two molecular clusters containing eight ferrocene units and four centres based on lanthanide hydroxo groups. This is the maximum number of ferrocene units anchored to any metal-heteroatom framework reported to date. They are interested in the air-stable multiferrocene assemblies based on this lanthanide oxygen cluster core. 

Applications of these compounds are found in the design of electron reservoirs, recognition of anionic species, as enzyme sensors and as models for fixation of multi-organometallic fragments on a metal oxide or carbide surface. Despite the potential of these molecular clusters, only a few main group and transition metal based clusters have been previously reported. 

 

Roesky hopes this research will allow the synthesis of even larger assemblies and the production of single molecular magnets via insertion of paramagnetic metals, although he sees the development of a rational synthetic approach for such assemblies a challenge.  

Helen Lunn