Ma Z.,Key Laboratory of Environmentally Friendly Chemistry and Applications of |
Wang P.,Key Laboratory of Environmentally Friendly Chemistry and Applications of |
Zhou G.,Xiangtan University |
Tang J.,Xiangtan University |
And 3 more authors.
Journal of Physical Chemistry C | Year: 2016
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 Au20+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. © 2016 American Chemical Society.