以酯端基PAMAM树形分子为模板在N，M-二甲基甲酰胺溶剂中制备金纳米粒子

用UV-vis、FT-IR光谱研究了HAuCl4和酯端基聚酰胺胺(PAMAM)树形分子在N，N-二甲基甲酰胺(DMF)溶剂中的相互作用，提出HAuCl4与树形分子之间的络合机理：[AuCl4]^-离子与质子化叔胺基团形成离子对，Au^3 离子与PAMAM树形分子上的酯基和酰胺基团形成配位作用。在DMF溶剂中酯端基PAMAM树形分子与HAuCl4配位后用柠檬酸钠还原形成金纳米粒子，UV-vis光谱和TEM图像分析表明了随树形分子代数的增加，金纳米粒子的直径减小，并提出了树形分子-金纳米复合物的结构模型：(1)较低代数的树形分子环绕在金粒子的外围；(2)在较高代数的树形分子空腔内部封装金纳米粒子。

Preparation of Gold Nanoparticles in N,N-dimethylformamide in the Presence of Methyl Ester Terminated Poly(amidoamine) Dendrimers

The interaction of HAuCl_4 and poly(amidoamine) dendrimers (PAMAM) with terminal methyl ester groups was investigated in N,N-dimethylformamide (DMF) by UV-vis and FT-IR spectroscopies. Three types of interaction are suggested: (a) ion pair formation between AuCl-_4 and protoned tertiary amine of PAMAM dendrimer, (b) chelation of Au 3+ by terminal methyl ester groups, and (c) chelation of Au 3+ by amide groups within PAMAM dendrimers. Gold nanoparticles were prepared by reduction of HAuCl_4 with sodium citrate in the presence of PAMAM dendrimers with surface methyl ester groups in DMF. The size of gold nanoparticles decreased with an increase of dendrimer generation. The gold nanoparticles prepared in DMF in the presence of dendrimer were highly monodispersed. In addition, we discussed how the dendrimers acted as templates for the preparation of gold nanoparticles. There are two possibilities for gold-dendrimer nanocomposites: one is that the gold nanoparticle is surrounded by several dendrimers and the other is that gold nanoparticles are encapsulated in the dendrimers.