Discrete Silver(I)-Palladium(II)-Oxo Nanoclusters, {Ag Pd } and {Ag Pd }, and the Role of Metal-Metal Bonding Induced by Cation Confinement.

We introduce the class of discrete silver(I)-palladium(II)-oxo nanoclusters with the preparation of {Ag Pd } and {Ag Pd }. Both polyanions represent the first examples of noble metal-capped polyoxo-noble-metalates in a fully inorganic assembly, featuring an unprecedented host-guest mode containing hetero- and homometallic Ag-Pd and Ag-Ag bonding interactions. Comprehensive theoretical calculations suggest that the Ag-Pd metallic bonds originate partially from surface confinement of Ag guest ions onto the anionic polyoxopalladate host that is induced by strong electrostatic forces.

Heptanickel(ii) double-cubane core in wells-dawson heteropolytungstate, [Ni7(OH)6(H2O)6(P2W15O56)2](16-).

The hepta-Ni(2+)-containing 30-tungsto-4-phosphate(v) [Ni7(OH)6(H2O)6(P2W15O56)2](16-) (1) has been synthesized in aqueous, slightly basic medium under conventional reaction conditions, and charactarized via different physical methods. Single-crystal XRD showed that 1 consists of a corner-fused double-cubane {Ni7(OH)6(H2O)6}(8+) fragment sandwiched by two trilacunary [P2W15O56](12-) units. Polyanion 1 is solution-stable as shown by (31)P NMR.

Alkaline earth guests in polyoxopalladate chemistry: from nanocube to nanostar via an open-shell structure.

The three novel, discrete palladium(II)-oxo clusters [CaPd12O8(PhAsO3)8](6-) (CaPd12), [SrPd12O6(OH)3(PhAsO3)6(OAc)3](4-) (SrPd12), and [BaPd15O10(PhAsO3)10](8-) (BaPd15) encapsulating alkaline earth metal ions were prepared and fully characterized by a multitude of solution and solid-state physicochemical techniques. We have discovered a structure-directing template effect induced by the respective size of the alkaline earth guest ion, which determines the detailed condensation arrangement of the peripheral Pd(II)-oxo shell. The unprecedented SrPd12 with an open-shell type structure is of particular importance and reflects a successful strategy for deliberate design of new structural classes of polyoxo-noble-metalates.

Synthesis, magnetism, and electrochemistry of the Ni14- and Ni5-containing heteropolytungstates [Ni14(OH)6(H2O)10(HPO4)4(P2W15O56)4]34- and [Ni5(OH)4(H2O)4(β-GeW9O34)(β-GeW8O30(OH))]13-.

The two Ni(2+)-containing heteropolytungstates [Ni14(OH)6(H2O)10(HPO4)4(P2W15O56)4](34-) (Ni14) and [Ni5(OH)4(H2O)4(β-GeW9O34)(β-GeW8O30(OH))](13-) (Ni5) have been successfully synthesized in aqueous, basic media under conventional reaction conditions, and they were characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric and elemental analyses, electrochemistry, and magnetic studies. The cyclic voltammetry (CV) patterns of Ni14 and Ni5 showed chemically reversible multielectronic waves for slow scan time scales. For Ni14, an important acidity inversion effect between its reduced forms was observed.

The selenite-capped polyoxo-4-aurate(III), [Au(III)4O4(Se(IV)O3)4]4-.

The discrete heteropolyaurate [Au(III)(4)O(4)(Se(IV)O(3))(4)](4-) (Au(4)Se(4)) represents only the second member of this class ever reported, and was synthesized via one-pot room temperature condensation in aqueous medium. was structurally characterized in the solid state and in solution by single-crystal XRD, TGA, FT-IR, (77)Se NMR, mass spectrometry and electrochemistry.