Universität zu Köln

Zopes, David, Stein, Benjamin, Mathur, Sanjay and Graf, Christina (2013). Improved Stability of Naked Gold Nanoparticles Enabled by in Situ Coating with Mono and Multivalent Thiol PEG Ligands. Langmuir, 29 (36). S. 11217 - 11227. WASHINGTON: AMER CHEMICAL SOC. ISSN 0743-7463

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Abstract

Unprotected (naked) gold nanoparticles with high monodispersity (< d >, 5.5 +/- 0.5 nm) were obtained in a facile and single-step microwave assisted hydrolytic decomposition of the molecular precursor [NMe4][Au(CF3)(2)]. Given their chloride free surface chemistry, the as-obtained gold nanoparticles were in situ functionalized with mono-, di-, and trivalent thiolated PEG ligands in order to study the influence of multivalent character of the ligands on the stability of the colloidal solutions For this purpose, a novel tridentate ligand was synthesized and the previously reported syntheses of mono- and divalent thiol ligands were improved. Owing to the pristine character of the Au nanoparticles no ligand exchange was required, and the colloidal and chemical stability of the mono- and multivalent functionalized particles purely depended on the ligating ability of the thiolated groups. In situ-functionalized Au nanoparticles showed a strikingly (2 orders of magnitude higher) improved stability against small nucleophiles such as sodium cyanide compared to gold nanoparticles coated with citrate ligands and functionalized via a ligand-exchange reaction. The monovalent thiol PEG ligand produced most stable colloids against cyanide, which is explained by a strongly increased numerical ligand-density on the surface. Gold colloids stabilized by di- and trivalent ligands exhibited high stability in aqueous solutions with high NaCl concentrations (2 M) in contrast to those functionalized with the monovalent PEG ligand, which were only temporally stable in dilute NaCl solutions. The beneficial effect of the multivalence of the ligands was further demonstrated by the incorporation of an additional chelating ligand (dithiothreitol) to the colloidal dispersions.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Zopes, David UNSPECIFIED UNSPECIFIED UNSPECIFIED Stein, Benjamin UNSPECIFIED UNSPECIFIED UNSPECIFIED Mathur, Sanjay UNSPECIFIED UNSPECIFIED UNSPECIFIED Graf, Christina UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-475970
DOI:	10.1021/la4012058
Journal or Publication Title:	Langmuir
Volume:	29
Number:	36
Page Range:	S. 11217 - 11227
Date:	2013
Publisher:	AMER CHEMICAL SOC
Place of Publication:	WASHINGTON
ISSN:	0743-7463
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language FUNCTIONALIZATION; STABILIZATION; COMPLEXES; POLYMER; DESIGN Multiple languages Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/47597