Sensitivity of Structural and Electronic Properties of Gold-Thiolate Nanoclusters to the Atomic Composition: A Comparative X-ray Study of Au₁₉(SR)₁₃ and Au₂₅(SR)₁₈

Journal Article · Mon Mar 04 04:00:00 EST 2013 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/jp309283y· OSTI ID:1056696

Chevrier, Daniel M; MacDonald, Mark A; Chatt, Amares; Zhang, Peng; Wu, Zhikun; Jin, Rongchao ^[1]

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1. Dalhousie U.

With the recent successful synthesis of an increasing number of atomically precise thiolate–gold nanoclusters (NCs), there are growing demands for a better understanding of their atomic structures and structure–property relationships in response to composition change. Herein, we present X-ray experimental results on structural and electronic properties of a recently synthesized gold–thiolate nanocluster, Au₁₉(SR)₁₃, in comparison with the structurally well-known Au₂₅(SR)₁₈ reference. The atomic structure of Au₁₉(SR)₁₃ was first probed with extended X-ray absorption fine structure (EXAFS). A multishell EXAFS fitting method (consisting of one Au–S and three Au–Au shells) allowed for a detailed structural comparison of the two nanoclusters, which revealed a sizable increase of the bond distances between the surface–surface and surface–staple Au atoms upon the decrease of Au atoms in the nanocluster. X-ray photoemission experiments and ab initio calculations further demonstrated the sensitive change of electronic properties of the nanoclusters when the cluster composition was varied, that is, the Au₁₉(SR)₁₃ nanocluster has a differently shaped and positively shifted Au 5d band relative to Au₂₅(SR)₁₈. These experimental findings highlight the sensitivity of the local structure and electronic properties of thiolate-gold nanoclusters to even a small change of the metal core from Au₁₃ to Au₁₁.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: OTHERFOREIGNUNIVERSITYU.S. AIR FORCE- OFFICE OF SCIENTIFIC RESEARCH
• OSTI ID: 1056696
• Journal Information: Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 47 Vol. 116; ISSN 1932-7447
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: ENGLISH