A1 Journal article (refereed)
Dynamic Stabilization of the Ligand-Metal Interface in Atomically Precise Gold Nanoclusters Au68 and Au144 Protected by meta-Mercaptobenzoic Acid (2017)

Tero, T.-R., Malola, S., Koncz, B., Pohjolainen, E., Lautala, S., Mustalahti, S., Permi, P., Groenhof, G., Pettersson, M., & Häkkinen, H. (2017). Dynamic Stabilization of the Ligand-Metal Interface in Atomically Precise Gold Nanoclusters Au68 and Au144 Protected by meta-Mercaptobenzoic Acid. ACS Nano, 11(12), 11872-11879. https://doi.org/10.1021/acsnano.7b07787

JYU authors or editors

Publication details

All authors or editors: Tero, Tiia-Riikka; Malola, Sami; Koncz, Benedek; Pohjolainen, Emmi; Lautala, Saara; Mustalahti, Satu; Permi, Perttu; Groenhof, Gerrit; Pettersson, Mika; Häkkinen, Hannu

Journal or series: ACS Nano

ISSN: 1936-0851

eISSN: 1936-086X

Publication year: 2017

Volume: 11

Issue number: 12

Pages range: 11872-11879

Publisher: American Chemical Society

Place of Publication: Washington

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1021/acsnano.7b07787

Publication open access: Not open

Publication channel open access:

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/56621

Abstract

Ligand-stabilized, atomically precise gold nanoclusters with a metal core of a uniform size of just 1-3 nm constitute an interesting class of nanomaterials with versatile possibilities for applications due to their size-dependent properties and modifiable ligand layers. The key to extending the usability of the clusters in applications is to understand the chemical bonding in the ligand layer as a function of cluster size and ligand structure. Previously, it has been shown that monodispersed gold nanoclusters, stabilized by meta-mercaptobenzoic acid (m-MBA or 3-MBA) ligands and with sizes of 68-144 gold atoms, show ambient stability. Here we show that a combination of nuclear magnetic resonance spectroscopy, UV-vis absorption, infrared spectroscopy, molecular dynamics simulations, and density functional theory calculations reveals a distinct chemistry in the ligand layer, absent in other known thiol-stabilized gold nanoclusters. Our results imply a low-symmetry C1 ligand layer of 3-MBA around the gold core of Au68 and Au144 and suggest that 3-MBA protects the metal core not only by the covalent S-Au bond formation but also via weak π-Au and O=C-OH···Au interactions. The π-Au and -OH···Au interactions have a strength of the order of a hydrogen bond and thus are dynamic in water at ambient temperature. The -OH···Au interaction was identified by a distinct carbonyl stretch frequency that is distinct for 3-MBA-protected gold clusters, but is missing in the previously studied Au102(p-MBA)44 cluster. These thiol-gold interactions can be used to explain a remarkably low ligand density on the surface of the metal core of these clusters. Our results lay a foundation to understand functionalization of atomically precise ligand-stabilized gold nanoclusters via a route where weak ligand-metal interfacial interactions are sacrificed for covalent bonding.

Keywords: gold; clusters; molecular dynamics; NMR spectroscopy; spectroscopy; carboxylic acids

Free keywords: gold nanocluster; thiols; vibrational spectroscopy

Contributing organizations

Related projects

Ministry reporting: Yes

Reporting Year: 2017

JUFO rating: 3