Dendrimer complexes: Fine control of metal assembly in macromolecules

Abstract

New phenylazomethine dendrimers have been developed, with each dendrimer having a unique single structure. From ultraviolet-visible absorption spectra, we determined that stannous chloride added to dendritic polyphenylazomethine (DPA) was assembled in a stepwise manner from the core shell to the periphery. The selective binding was achieved by the electron density gradient formed in the dendrimer, and it was confirmed by shell-selective imine reduction, transmission electron microscopy, and NMR measurements. The complex formation constants of the respective shells were estimated to be considerably different by a simulation analysis of ultraviolet-visible absorption spectra. The reversible assembly and release of iron into and out of the dendrimer were possible by electrochemical oxidation and reduction, respectively. DPA with a porphyrin at the core was found to function as an effective reduction catalyst of carbon dioxide. DPA with aryl amine at the core was demonstrated to function as a hole-transporting material in electroluminescent devices. © 2005 wiley Periodicals, Inc.