Copper, gold and nickel clusters with and without metal–metal bonds in 50 years of Fackler group chemistry

• Copper(I) cubes and clusters with sulfur ligands.
• Anion encapsulating clusters.
• Gold clusters and chains with carbon, nitrogen and sulfur ligands.
• Gold catalyst precursors.
• Nickel and cobalt cluster catalyst precursors.

Clusters have played a strong role in the chemistry of the Fackler group for about 50 years (Fackler 1989) [1]. This paper reviews some of the chemistry we have uncovered with copper, gold and nickel which have produced several unanswered questions. Although electron-pair bonding between the metal atoms in these clusters is present only in the gold(II) compounds described, cuprophilic and aurophilic metal–metal interactions are present in the compounds described for copper and gold. In the tri-i-butyl aluminum reduced nickel catalyst system which leads to the formation of cis-polybutadiene, the role of any metal–metal interactions is unknown.

This paper reviews some of the chemistry the Fackler group has uncovered with copper, gold and nickel clusters. Several unanswered questions remain. Although the bonding in most of the clusters described is not classical electron pair metal–metal bonding, cuprophilic and aurophilic metal–metal interactions are present with these two elements. The copper clusters appear to have an essential role in the chemistry of automotive oil additives. Gold clusters have been implicated in the catalytic low temperature oxidation of CO and also may be involved in other heterogeneous and homogeneous catalysis. In the nickel catalyst system which successfully produced cis-polybutadiene under adiabatic conditions, metal–metal interactions are not present in the catalyst precursor cluster. However, reduction with alkyl aluminum also is essential. The extents of metal–metal interactions in the reduced polymetallic catalyst are unknown. Efforts to characterize the pre-catalyst cluster and the actual catalyst are summarized.Figure optionsDownload as PowerPoint slide