Heterometal assembly in dendritic polyphenylazomethines

Fine-controlled metal-organic hybridization is strongly desired for advanced nano-materials. Dendrimers are highly branched organic macromolecules with successive layers or "generations" of branch units surrounding a central core. Metal-organic hybrid versions have also been produced by trapping metal ions or metal clusters within the voids of dendrimers. Here, we report a technique to form a dendritic organic structure, which includes various metals, with fine control over the number and location of the metal salts through a radial stepwise complexation. FeCl₃, GaCl₃,VCl ₃, and SnCl₂ were decorated on a phenylazomethine dendrimer with 4th generations at the first, second, third, and forth layers, respectively. These stepwise complexation and heterometal assembling were also supported by TEM observation, ⁵⁷Fe Mössbauer spectroscopy, XPS measurement, and NMR spectroscopy.