Multimetallic Sandwich Compounds - a Brief Introduction

As the most prevalent structure in organometallic chemistry, sandwich compounds, defined as two cyclic aromatic hydrocarbon ligands flanking one metal center, has played a central role on the stage of organometallic chemistry and catalysis ever since the seminal structure of ferrocene (CpjFe) was elucidated in 1952 [161]. However, this chemistry had never been extended into compound mono-layers of multiple metal atoms in place of the one metal center as the filling of the sandwich until 

After the seminal discovery of multimetallic sandwich compounds 231 and 232, several palladium [164], platinum [165], and Pd/Pt heterometallic [166] sandwich compounds belonging to the new and burgeoning family were synthesized and characterized. Furthermore, it was found that the assembly of the multimetallic core can be tuned intermolecularly [167] or intramolecularly [168] by redox reactions. It can be foreseen that this novel and unique family of compounds will flourish in the near future and find its own position in catalysis. 

Cotton, F.A., Murillo, C.A., and Walton, R.A. (2005) Multiple Bonds between Metal Atoms, 3rd edn. Chapter 14, Springer Science and Business Media. 

Majoumo-Mbe, E, Kuhl, O., Lonnecke, P, Silaghi-Dumitrescu, I., and Hey-Hawldns, E. (2008) Dalton Trans., 3107. 

(1999) Metalorganic Catalysts for Synthesis and Polymerization, Springer-Verlag, Berlin, Heidelberg, pp. 616-628. 

---