The Octahedral M6Y8 And M6Y12 Clusters of Group 4 and 5 Transition Metals

Publisher Summary This chapter discusses the octahedral M 6 Y 8 and M 6 Y 12 clusters of group 4 and 5 transition metals. Octahedral clusters of the electropositive metals, groups 3 to 7, are stabilized by π-donor ligands such as halides, chalcogenides, and alkoxides, but the majority accessible to solution chemistry is the halide complexes. Dilution of the pyridine surface with coadsorbed thiolphenol, a noncoordinating moiety, reduces the amount of cluster adsorbed to the surface and the average number of triflate ligands displaced by surface pyridine. The number of triflate ligands remaining on the surface-bound cluster may be adjusted with the thiolphenol/mercaptopyridine ratio. The different coordination environments about the core in the resulting material have been identified with differential pulse voltammetry. Both the α- and β-nitrogens of the azide ligand bind the cations, whereas only the sulfur atoms of the thiocyanate groups coordinate to the alkali metals. In addition to cation bridges, water molecules connect the azide ligands of adjacent clusters via hydrogen bonding.