本研究以含聯吡啶的單硫醇和雙硫醇分子，修飾金奈米粒子，進行離子感測及自我組裝的研究。金奈米粒子的製備，是將含檸檬酸鈉 ( sodium citrate )的金氯酸 ( HAuCl4 )水溶液，以硼氫化鈉( NaBH4 )還原，得到粒徑為3 nm的金奈米粒子。另以1,10-二氮雜菲( 1,10-phenanthroline )為起始物，成功合成出含聯吡啶的單硫醇( HSC12MEBiox )和雙硫醇( HSC12EBiox )。接著將合成的單硫醇和雙硫醇分別與1-己硫醇( 1-hexanethiol, C6SH )及1-癸硫醇( 1-decanethiol, C10SH )，以不同的莫耳比例混合，修飾在3 nm的金奈米粒子上。我們將各種金屬離子( Ba2+、Mn2+、Co2+、Ni2+、Cu2+、Ag+、Zn2+、Cd2+、Hg2+、Pb2+ ) ，分別加入此一具有特殊官能基的金奈米粒子水溶液，偵測其變化，根據UV-vis吸收光譜及穿透電子顯微鏡( TEM )的結果，發現此系統對Hg2+離子有專一選擇性。並且發現，在加入汞離子後，金奈米粒子呈現球狀聚集，且HSC12MEBiox-AuNPs的球狀聚集會隨著汞離子濃度增加而增大，或 HSC12EBiox-AuNPs的球狀聚集會串聯起來呈線形排列。 Gold nanoparticles solution was prepared by sodium borohydride method. Particle size of 3 nm was characterized by electronic absorption spectra and transmission electron microscopy. A di-thiol compound, bis(12-mercaptododecyl)2,2’-bipyridie-3,3’-dicarboxylate(HSC12EBiox), and a mono-thiol compound, (Methyl)[12-mercaptododecyl]2,2’-bipyridine-3,3’-dicarboxylate (HSC12MEBiox), was synthesized. Functionalized AuNPs containing these agent with/without co-capping agents was prepared and used for metal ion sensing. The co-capping agent is decanethiol or hexanethiol. The AuNPs(3 nm) employed as chromophores were capped with agent through Au–S bonds. If their aggregation were to be driven by the recognition and binding of heavy-metal ions, the color change would allow visual sensing of the ions. Treating of these solutions with Ba2+、Mn2+、Co2+、Ni2+、Cu2+、Ag+、Zn2+、Cd2+、Pb2+ and Hg2+ ion, we found that 3(1-decanethiol)/HSC12EBiox-AuNPs and 1-hexanethiol/ HSC12MEBiox-AuNPs system could successfully detect mercury ion and have high selectivity. The TEM experimental results revealed that the 3DT/HSC12EBiox-AuNPs self-assembly aggregate into soluble 1-D chains in addition of Hg2+. The HT/HSC12MEBiox-AuNPs self-assembly aggregate into soluble larger spherical particles of 100 nm. We unveiled a new homogeneous assay-using bipyridinyl-alkyl-thiol modified AuNPs which has highly selective and sensitive detection of Hg2+ was synthesized. In this study, we took advantage of the aggregation-induced color changes of HSC12EBiox and HSC12MEBiox-functionalized AuNPs in aqueous solutions to develop a highly selective optical sensor for Hg2+.
