Site Preference Effects in Heterometallic Clus

In organometallic chemistry new and versatile synthetic routes have been for isolating heterometallic ligated cluster compounds wit! up to 44 me Naked mixed metal clusters with size ranges of 10-50 A are of imp catalytic processes and smaller naked heterometallic clusters have been molecular beam experiments. These rather different areas raise commor concerning the relative dispositions of the two types of metal atoms. In 1 a general analysis of site preference effects derived from molecular orbi bation theory methods is developed. For naked clusters the site prefe controlled primarily by the relative strengths of the metal-metal bonds metal that forms stronger metal-metal bonds occupying interstitial or nectivity sites. For ligated clusters these effects are important but the strengths of the metal-ligand bonds can also play a decisive role.