Supported Metal Chains

In this chapter, we describe linear metal chain compounds, consisting of at least three metal ions, supported by ligand systems. Extended metal atom chains (EMACs) of Cr, Co, Ni, and Cu, supported by polypyridylamide ligands, are discussed. This is followed by linear and bent Pd chains sandwiched by unsaturated hydrocarbons. Unsupported linear metal chain compounds are discussed in subsequent sections. Because synthetic protocols and the bonding schemes are different for different metals, our discussion is classified according to metal ions. 

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Catalysis by Metal Ousters in Zeolites. There is an increasing interest in the use of metal clusters stabilized in zeolites. One objective of such work is to utilize the shape and size constraints inherent in these support materials to effect greater selectivities in typical metal-catalysed reactions. Much work has been concerned with carbon monoxide hydrogenation, and although the detailed nature of the supported metals so obtained is not well understood, there is clear evidence of chain limitation in the Fischer-Tropsch process with both RuY zeolites and with HY and NaY zeolites containing Fe3(CO)22- In the former case there is a drastic decline in chain-growth probability beyond C5- or C10-hydrocarbons depending upon the particle size of the ruthenium metal. 

Polymerization Ziegler-Natta, supported metal oxides such as PhiUps, Unipol and metallocene Stereospecific chain formation required weak interaction/complexation with any initiators/catalysts metal coordination complexes required... 

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