Au36(SPh)24 Nanomolecules: X-ray Crystal Structure, Optical Spectroscopy, Electrochemistry, and Theoretical Analysis

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• 作者：Praneeth Reddy Nimmala ; Stefan Knoppe ; Vijay Reddy Jupally ; Jared H. Delcamp ; Christine M. Aikens ; Amala Dass
• 刊名：Journal of Physical Chemistry B
• 出版年：2014
• 出版时间：December 11, 2014
• 年：2014
• 卷：118
• 期：49
• 页码：14157-14167
• 全文大小：701K
• ISSN：1520-5207

文摘

The physicochemical properties of gold:thiolate nanomolecules depend on their crystal structure and the capping ligands. The effects of protecting ligands on the crystal structure of the nanomolecules are of high interest in this area of research. Here we report the crystal structure of an all aromatic thiophenolate-capped Au₃₆(SPh)₂₄ nanomolecule, which has a face-centered cubic (fcc) core similar to other nanomolecules such as Au₃₆(SPh-tBu)₂₄ and Au₃₆(SC₅H₉)₂₄ with the same number of gold atoms and ligands. The results support the idea that a stable core remains intact even when the capping ligand is varied. We also correct our earlier assignment of 鈥淎u₃₆(SPh)₂₃鈥?which was determined based on MALDI mass spectrometry which is more prone to fragmentation than ESI mass spectrometry. We show that ESI mass spectrometry gives the correct assignment of Au₃₆(SPh)₂₄, supporting the X-ray crystal structure. The electronic structure of the title compound was computed at different levels of theory (PBE, LDA, and LB94) using the coordinates extracted from the single crystal X-ray diffraction data. The optical and electrochemical properties were determined from experimental data using UV鈥搗is spectroscopy, cyclic voltammetry, and differential pulse voltammetry. Au₃₆(SPh)₂₄ shows a broad electrochemical gap near 2 V, a desirable optical gap of 鈭?.75 eV for dye-sensitized solar cell applications, as well as appropriately positioned electrochemical potentials for many electrocatalytic reactions.