| octa(diacetic aminophenyl)silsesquioxanes (OAAPS) was synthesized, and used as stabilizers for preparing a series of noble nanometal clusters. Some corresponding researches were done as follows:(1) Octaphenylsilsesquioxanes (OPS) were synthesized by hydrolysis of phenyltrichlorosilanes as a raw material. The phenyl groups of OPS can be nitrated, and the resulting octa(nitrophenyl)silsesquioxanes (ONPS) reduced by aminophenyl groups to obtain octa(aminophenyl)silsesquioxanes (OAPS). Then OAPS were reacted with methyl chloroacetate to produce octa(dimethylacetate aminophenyl) silsesquioxanes (OMAAPS). The final dendrimer of octa (diacetic aminophenyl) silsesquioxanes (OAAPS) can be gotten by hydrolysis of OMAAPS. The structures of these five cubic silsesquioxanes were characterized by 'HNMR, FT-IR, and element analysis.(2) OAAPS were used as stabilizers for preparing nanometal (Pt, Pd, Ru and Au) clusters using NaBH4 as a reducing agent. The synthesized catalysts were characterized by UV-vis, FT-IR, XRD, and TEM. With the same molar ratio of metal/OAAPS (metal/OAAPS=7:1), the resulting metal nanoparticles were small. The average diameters of Pt(0), Pd(0), Ru(0) and Au(0) nanoparticles were 1.6±0.3, 1.4±0.2, 1.3±0.2 and 2.5±0.7nm, respectively. The stability and catalytic activity of metal colloidal solution stabilized by OAAPS strongly depended on the molar ratio of metal/OAAPS. When the molar ratio of metal (Pt, Pd, Ru, Au) and OAAPS was in the range of 1-30, 1-35, 1-25, 1-40 respectively, the slightly basic colloidal solution of metal@OAAPS were stable without precipitation at room temperature for several weeks, or even more than one year. The conversion of benzaldehyde changed 85.77％to 98.77％when the molar ratio of Pd/OAAPS is 1:1 to 15:1. The hydrogenation of phenyl aldehydes was chosen to be the model reaction to investigate the catalytic activities of metallic (Pt@OAAPS, Pd@OAAPS and Ru@OAAPS) colloids (metal/OAAPS=10:1). Pt colloids showed its catalytic activity for the hydrogenation of benzaldehyde and 3-phenoxybenzaldehyde, turnover frequencies (TOF) of them was 28 and 31. And the conversion of benzaldehyde reached 97.9％after 4h, so Pd@OAAPS colloid was found to be effective for the hydrogenation of benzaldehyde. While Ru@OAAPS colloid seemed to not be a suitable catalyst for hydrogenation of phenyl aldehydes. In addition, the metallic nanoparticles stabilized by OAAPS were sensitive to the value of pH. The metallic colloidal catalysts can be recycled by simply adjusting the pH of the solution. Pd@OAAPS catalyst was recovered and recycled eight times without obvious loss of the catalytic activity for the hydrogenation of benzaldehyde, of that conversion was 92.54％after 3h.(3) Bimetallic (Pt/Pd, Pt/Au, Pt/Ag) nanoclusters protected by OAAPS were prepared by successive reduction. Monometallic Pt nanoparticles were firstly prepared by reducing PtCl62- in the refluxing of alcoholic solution. Then with the Pt nanoparticles as the "seeds", the second metal salt was added and was reduced by hydrogen gas to prepare bimetallic nanoparticles. The bimetallic nanoclusters were characterized by UV-vis, XRD and TEM. When the molar ratio of nmetal1//nmetal2=1:1, n((metal1+nmetal))/nOAAPS=30:1, the average diameters of Pt/Pd, Pt/Au and Pt/Ag bimetallic nanoparticles were 2.6±0.5nm, 3.1±0.7nm, 2.3±0.3nm, respectively. The catalytic hydrogenation of benzaldehyde and 3-phenoxybenzaldehyde were significantly enhanced in the presence of Pt/Pd bimetallic nanoparticles as compared to Pt or Pd monometallic nanoparticles. The conversion of benzaldehyde and 3-phenoxybenzal- dehyde reached 99.42％and 92.64％after 2h when Pt20/Pd10@OAAPS-30 bimetallic nanoclusters as the catalyst. The Pt/Pd metallic colloidal catalysts also can be recycled by simply adjusting the pH of the solution, and it displayed good catalytic activity after recycled five times. But as the same molar ratio, Pt/Au and Pt/Ag bimetallic colloid didn't show their catalytic activity for the hydrogenation of 3-phenoxybenzaldehyde. With Pt/Au and Pt/Ag catalysts, the conversion 3-phenoxy-benzaldehyde was only 22.79 and 2.36％.
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