Pd/PAMAM dendrimers nanoparticles (Pd DEN) with tunable size were prepared by Poly(amidoamine) (PAMAM) dendrimers-templated method, then Pd DEN were immobilized on SBA-15 by ultrasonic method to obtain SBA-15 supported Pd dendrimers nanoparticles (Pd SDEN). TEM and XRD results indicate that the parent structures of Pd nanoparticles and SBA-15 are well-maintained during the supporting process and Pd nanoparticles are highly dispersed inside the channels of SBA-15. The catalytic activity was studied by monitoring the reduction of p-nitrophenol photometrically. The results indicate that the catalytic activity of Pd SDEN is significantly enhanced compared to that of the corresponding DEN. The catalytic activity of the catalyst is well maintained after five cycles, resulting in the reaction rate reduced by only 4% and Pd DEN particles are still stable in the pores of zeolite.

Using a successive method, PAMAM dendrimer-encapsulated bimetallic PdPt nanoparticles have been successfully prepared with core-shell structures （Pd@Pt DENs）. Evidenced by UV-vis spectra, high resolution trans- mission electron microscopy, and X-ray energy dispersive spectroscopy （EDS）, the obtained Pd@Pt DENs are monodispersed and located inside the cavity of dendrimers, and they show a different structure from monometallic Pt or Pd and alloy PdPt DENs. The core-shell structure of Pd@Pt DENs is further confirmed by infrared measure- ments with carbon monoxide （IR-CO） probe. In order to prepare Pd@Pt DENs, a required Pd/Pt ratio of 1 ： 2 is de- termined for the Pt shell to cover the Pd core completely. Finally, a mechanism for the formation of Pd@Pt DENs is proposed.

G5.0-OH PAMAM dendrimers were used to prepare fluorescent silver clusters with weaker ultraviolet irradiation reduction method, in which the molar ratio of Ag+ to PAMAM dendrimers was the key factor to determine the geometry and properties of silver nanoparticles. The results showed that because of G5.0-OH PAMAM dendrimers as strong encapsulatores, when the molar ratios of Ag+ to PAMAM dendrimers was smaller than 5, the obtained Ag-n clusters (n<5) had line structures and "molecular-like" properties, which were highly fluorescent and quite stable in aqueous solution. Whereas when the molar ratios were between 5 and 8, the obtained Ag-n clusters were 2D structures and their fluorescence was weaker. When the molar ratio was larger than 8, the structure of silver nanoparticles was 3D and no fluorescence was observed from the obtained silver nanoparticles.

Pd nanoclusters templated by methoxycarbonyl-terminated poly(amidoamine)(PAMAM) dendri-mers were successfully prepared in methanol. The complexation between Pd2+ ions and dendrimers was investigated by UV-Vis and FTIR spectophotometric method. These results show that Pd2+ ions are coordinated with the interior amine groups of PAMAM dendrimers. As shown in HRTEM images, reduction with NaBH4 resulted in well-dispersed and nearly size monodisperse Pd nanoclusters(2 nm, FCC) encapsulated in dendrimers. The investigation of UV-Vis data indicates that the size of particle increases with the metal-to-dendrimer molar ratio. Besides, due to the close-packed spherical periphery and rich ligands in interior cavities, dendrimers of higher generation are more effective for preparing Pd DENs with smaller size and better dispersion.

Poly(amidoamine) (PAMAM) dendrimers have attracted attention because of their well-defined molecule structures and chemical versatility, which also complicate the mechanism of interactions between metal ions and PAMAM dendrimers. To further understand the complexation of dendrimers with metal ions, the interactions between Pd2+ ions and G4.5-COOCH3 PAMAM dendrimers were investigated by UV-vis and FTIR spectrophotometric method. The results show that the addition of K2PdCl4 results in covalent attachment of the PdCl alcoholysis product of this complex to tertiary amines within the dendrimers under the appropriate conditions. This process was also supported by X-ray photoelectron spectroscopy data of the new complex which indicated a 1 : 3 Pd/Cl ratio. The maximum loading of 80 Pd2+ ions within the G4.5-COOCH3 dendrimers and the best pH value of 8.3 for complexation system are also obtained. Details regarding the Pd species present in solution of different chemical environments are reported. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Uniform and well-dispersed photoluminescent semiconductor CdS (cadmium sulfide) QDs (quantum dots) were in situ prepared inside Generation 4.0-NH2 PAMAM (polyamidoamine) dendrimers in methanol, methanol and water mixed solutions of volume ratio 1:9, respectively. The prepared solutions containing photoluminescent semiconductor CdS QDs were utilized for detection of cyanoacrylate ester fumed fingerprints on tinfoil. The results show that fumed latent fingerprints treated with prepared CdS/PAMAM nanocomposites in methanol, 1:9 methanol:water mixed solutions emit pale yellow–green and orange luminescence respectively under ultraviolet excitation of 365nm from an UV LED. Fumed fingerprints were successfully detected with good resolving rate and the mechanism was studied in detail.

The complexation of pt(2+) ions with G5.5-COOCH3 PAMAM dendrimers was investigated by UV-VIS and FT-IR spectral methods, showing that Pt2+ ions are coordinated with the interior amino groups of dendrimers. It needs more time for the complexation reaction to come to balance with the increase of molar ratios of pt(2+) ions to dendrimers. The maximum loadings of 50 similar to 55 Pt2+ ions within the G5.5-COOCH3 dendrimers were also obtained. Following reduction with NaBH4 resulted in spherical and well-dispersed Pt nanoparticles (average size < 2 nm) encapsulated in the dendrimers as shown in HRTEM images. When the ratio of pt2+ Ions to dendrimers was 10, the yielded Pt nanoparticles with smaller sizes and a narrow distribution were intradendrimer templated. When the ratio of Pt2+ ions to dendrimers was 50, new partially formed Pt nanoparticles with larger sizes and a broad distribution were interdendrimer templated.