Control over the preference for binding sites of polyoxometalates to silver ethynide clusters by surface charge modification.

A polyoxometalate-silver ethynide composite cluster, [Ag42(CO3){C≡CC(CH3)3}27(α-A-SiW9Nb3O40)2](-) (1), demonstrates that we can select the binding site of a polyoxometalate to the silver alkynide cluster by tuning the surface charge of the precursor polyoxometalate. Multidimensional and multinuclear NMR spectra revealed that 1 maintains its precise atomic connectivity in the solution.

Trinuclear and Tetranuclear Re(I) Rings Connected with Phenylene, Vinylene, and Ethynylene Chains: Synthesis, Photophysics, and Redox Properties.

A series of highly luminescent trinuclear and tetranuclear ring-shaped Re(I) complexes wherein the Re units are linked with rigid bidentate phosphine ligands, namely, bis(diphenylphosphino)-p-phenylene, -trans-vinylene, and -ethynylene, were synthesized and fully characterized. Their strong emissive properties and the long lifetimes of their triplet metal-to-ligand charge transfer excited states originate primarily from enhanced, rigidity-induced interligand interactions between the 2,2'-bipyridine (bpy) ligand and the phenyl groups of the phosphine ligands. In addition, another type of interligand interaction was also observed between the bpy ligand and the phosphine-bridging group; this interaction also strongly affected the photophysical and redox properties of the Re-rings.