Total Structure Determination of the Largest Alkynyl-Protected fcc Gold Nanocluster Au110 and the Study on Its Ultrafast Excited-State Dynamics

Great attention has been paid to nanoclusters having face-centered-cubic (fcc) metal kernels, because of the similarity of metal packing to that of bulk gold. So far, there is no precedent example of an all-alkynyl-protected fcc gold nanocluster with more than 100 gold atoms. We report the synthesis and total structure determination of an alkynyl-protected gold nanocluster [NEt3H](2)[Au-110(p-CF3C6H4C C)48] (Au-110). It has an fcc Au-86 kernel with 24 peripheral Au(C CR)(2) staples. The Au-86 kernel consists of six close packing layers in the pattern of Au-6:Au-16:Au-21:Au-21:Au-16:Au-6. Electronic absorption spectroscopy shows Au-110 has a molecular-like discrete electronic structure, and transient absorption experiments reveal its nonmetallic nature.