Synthesis, Interactions And Catalytic Properties Of Water-Soluble Porphyrins With (PAMAM) Dendrimers

Porphyrins are active centers of many natural proteins and enzyme. They play a great role in the transfer, reserve, activation of oxygen and photosynthesis in the life activities. Tetrakis(p-sulfonatephenyl)porphyrin (H2TPPS) is a kind of phototherapy drugs with good performance. (PAMAM)dendrimers are new artificial macromolecules with tree-like structure. They are hyperbarnched and monodisperse three-dimensional molecules with defined molecular structure. Dendrimers have been successfully proved as promising nanocarriers for drug delivery due to their greater water-solubility, bioavailability and compatibility for the drug molecules rendering. It is a great importance to study the interactions between water-soluble porphyrins and dendrimers.Water-soluble porphyrin: tetrakis(p-sulfophenyl) porphyrin (H2TPPS) and its metalloporphyrin complex (FeTPPSCl and ZnTPPS) have been synthesized and characterized. The pH control for the reaction system and the use of the dialytic bag can efficiently increase the yield and purity of product. The structural traits and spectral properties have been discussed by Uv-vis, Fluorescence, 1H NMR and FT-IR spectroscopic methods.We investigated the interactions between water-soluble porphyrins and (PAMAM)dendrimers of full generations (G2, G4 and G6)and half generations(G1.5, G2.5 and G3.5). The binding numbers and equilibrium constants have been calculated according to host-guest principle. For the interactions between H2TPPS and dendrimers, the binding abilities become larger with generation increase of the dendrimers. As to the interations between ZnTPPS and dendrimers, the binding number and equilibrium constants are much determined by the dendrimer structure.FeTPPS/(PAMAM)dendrimer system were used as catalysts in 2, 4, 6- trichlorophenol oxidative dichlorination with H2O2 as oxidant, FeTPPS/(PAMAM)dendrimer G2/H2O2 system has been proved to be an efficient catalytic system and 18960 turnover numbers was obtained which was three times larger than that at the absence of the (PAMAM)dendrimers. The reaction rate and catalytic activity can be controlled by using different generation dendrimers.