Template-effect Of Poly (Amidoamine) Dendrimers In Synthesis Of Some Functional Inorganic Compounds

The Poly(amido-amine)(PAMAM) Dendrimers, which have hyper-branched, well defined and monodisperse structures, can be formed by reiterative reaction sequences starting from smaller molecules named "initiator core". And its molecular weight, size, shape and functional group over surface can be controlled by the reactions and synthetic building blocks used. Great attention has been paid to dendrimers in many fields, especially in synthesis of some functional inorganic materials.The poly(amidoamine) dendrimers (from 0.5 to 4.0 generations) were synthesized and characterized by FT-IR, NMR. The results and computational simulation data show that PAMAM dendrimer is a highly ordered, three-dimensional global macromolecule. Hollow ZnS spheres have been prepared in the presence of generation 3.5 poly(amidoamine) dendrimers with surface ester groups (G3.5-COOCH₃ PAMAM dendrimer) as synthetic matrix template. The products obtained were characterized. It was found that the concentration of PAMAM dendrimer has a significant influence on the formation of hollow ZnS spheres. The possible formation mechanism of the hollow spherical structure was also discussed. Copper cluster with good stability, well dispersion, smaller in diameter can be obtained in presence of G4-NH₂-PAMAM dendrimer and as a reductant under air. Change of the PH value of solution great influences the particle size, dispersion and stability. A polyoxometalate-terminated dendrimer nanocomposite based on ionic bonding between dendritic polyamidoamine (PAMAM) cations and polyoxometalate anions (PW₁₂O₄₀^3-) was synthesized and was characterized by FT-IR, DR-UV-vis, TG-DTA, ESR, SEM, XRD and TEM. The polyoxometalate-terminated dendrimer is a good example of modifying the dendrimer exterior by noncovalent interactions and shows reversible photochromic behavior.Furthermore, (NH₄)₄[PMo₁₁VO₄₀]·4H₂O nanometer powders were prepared by the solid state reaction of H₄PMo₁₁VO₄₀·13H₂O and (NH₄)₂C₂O₄·H₂O at room temperature and characterized by XRD, FT-IR, DRS, TEM, TGA and BET. The nanometer powders were used as a catalyst in the dehydration of cyclohexanol to cyclohexene and were showed higher catalytic activity than other catalyst. The experimental results show that...