The polar M-M` linkages in mixed-metal clusters may enhance substrate activation, and the potential for this should be greater when very different metals are used. However, most mixed-metal clusters contain metals from the same or adjacent groups; the synthesis of clusters with very different metals remains a major challenge. We have developed routes to certain mixed-metal clusters, reporting >95% of examples with Mo/W-Ir bonds thus far (the figure shows a Mo4Ir4 cluster with a capped pentagonal bipyramidal core). This project will explore the synthesis and chemistry of new group 6/group 9 mixed-metal clusters. The selectivity for certain types of catalysis will be explored in collaboration with the State Key Laboratory for Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences.