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Modification of gold nanoparticle surfaces with pyrenedisulfide in ligand-protected exchange reactions

Uznański P., Kurjata J., Bryszewska E.

Materials Science Poland

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2009

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Vol. 27, No. 3

659--670

EN

We provide a study of ligand place-exchange reaction on Au nanoparticles. Nanoparticles of the dimensions of 7-9 nm were fabricated by high-temperature anhydrous route in the presence of primary aliphatic amine. The advantage of weak coordination to gold, through the nonbonding electrons of the amino group, was to use in an exchange of an initial protective ligand. Therefore, among other stabilizing agents, photoactive dialkyldisulfide molecules functionalized with fluorescent pyrene moieties were attached. The photophysical properties of such a stabilized gold system were investigated during placeexchange reaction. Fluorescence studies show that the excimeric band, characteristic of bispyrene, disappears in the spectrum after binding to the gold NPs, indicating that pyrene molecules are adsorbed separately on the surface. Efficient quenching of monomeric emission suggests that deactivation of the fluorescent excited state occurs through a radiationless transition, probably a charge transfer one, formed due to prior electron transfer from pyrene moiety to gold. Kinetics of chemisorption of pyrene disulfide and its desorption in the presence of thiols was also studied, revealing that both processes comprise a fast and a slow component with an overall rate higher for the desorption.

2

High-temperature synthesis of gold nanoparticles - towards organized gold arrays

Uznański P., Amiens C., Chaudret B., Bryszewska E.

Scientific Bulletin. Physics / Lodz University of Technology

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2006

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Vol. 26

99-106

EN

We report high-temperature pathways for the synthesis of gold nanoparticles (NPs) which lead to larger particles and to narrower polydispersity of their dimensions. Two kinds of gold atom precursors: chloroauric acid HauCl4, and triphosphinogold oxonium salt, {O(AuPPh3)3}BF4, were used. The synthesis of NPs and their organization on a substrate was studied for stabilizing hexadecylamine ligand. In the case of oxonium salt the amine not only capes formed nanoparticles but also takes part in reduction of the gold atom precursor. This precursor enables narrowing size distribution of synthesized NPs which furthermore show a propensity to selforganization.

PL

W pracy przedstawiono wysokotemperaturowe syntezy nanocząstek (NCz) złota, które prowadzą do większych rozmiarów cząstek metalu w porównaniu z syntezami przeprowadzanymi w temperaturze otoczenia. zastosowano dwa rodzaje prekursorów atomów złota: kwasu tetracholrozłotowego HAuCl4ܩH2O oraz oksoniowej soli tryfosfinyzłota [O(AuPPh3)3]BF4. Syntezy NCz dla obydwu związków odbywały się w obecności ligandu heksadecyloaminy. W przypadku soli oksoniowej amina nie tylko tworzyła monowarstwowe pokrycia NCz, ale brała udział w etapie redukcji związku złota. NCz syntezowane z tego prekursora miały wąski rozkład rozmiarów i wykazywały silną skłonność do samoorganizacji na stałych podłożach.

3

Gold Nanoparticles from Oxonium Precursor: Synthesis in the Presence of Primary Amine and Characterization

Uznanski P., Amiens C., Chaudret B., Bryszewska E.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 11

1845-1855

EN

A convenient method of the synthesis of gold NPs with low polydispersity is described. Triphosphinogold oxonium salt [O(AuPPh3)3]BF4 in the presence of amine and dioxygen is a versatile gold atom source in mesitylene. The amine takes part in the reduction of gold(I) atom precursor. Therefore in a 1/1 Au(I)/hexadecylamine stechiometry, "naked" gold nanoparticles are produced which precipitate within some minutes from the solution and form a gold mirror. Only an excess of amine enables the synthesis of ligand-protected nanoparticleswhich furthermore display a great tendency to self-organize. Solvent effect on the course of the reaction is discussed.