Correlating the Structure and Optical Absorption Properties of Au76(SR)44 Cluster

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• 作者：Zhongyun Ma ; Pu Wang ; Guang Zhou ; Jian Tang ; Hengfeng Li ; Yong Pei
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：June 30, 2016
• 年：2016
• 卷：120
• 期：25
• 页码：13739-13748
• 全文大小：763K
• 年卷期：0
• ISSN：1932-7455

文摘

The atomic structure of recently synthesized thiolate-protected Au₇₆ cluster is theoretically predicted via a simple structural rule summarized from the crystal structures of thiolate-protected Au₄₄(SR)₂₈, Au₃₆(SR)₂₄, and Au₅₂(SR)₃₂ clusters. We find that Au₇₆(SR)₄₄ (N = 7) and recently reported Au₅₂(SR)₃₂ (N = 4), Au₄₄(SR)₂₈ (N = 3), Au₃₆(SR)₂₄ (N = 2), and Au₂₈(SR)₂₀ (N = 1) belong to a family of homologous Au_20+8N(SR)_16+4N clusters whose Au cores follow a one-dimensional polytetrahedral growth pathway. The Au₇₆(SR)₄₄ cluster is predicted to contain an anisotropic face-centered-cubic (fcc) Au core, which can be viewed as combination of two helical tetrahedra Au₄ chains and is remarkably different from the well-known spherical Au core in ligand-protected gold clusters in the size region of 1–2 nm. The intense near-infrared (NIR) absorption of Au₇₆(SR)₄₄ is attributed to the synergistic effect of anisotropic Au core structure and ligand protections. A plausible cluster-to-cluster transformation mechanism is further suggested.