Medium-Sized Au-58(SR)(30): A New Chiral Structure Evolving from Crystallized Au-40(SR)(24) and Au-49(SR)(27)

摘要

Predicting new stable structures via structural evolution has been proven to be a very effective method of obtaining the structures of thiolate-protected gold nanoclusters. Herein, we report a new medium-sized Au-58(SR)(30) structure evolving from crystallized Au-40(SR)(24) and Au-49(SR)(27) nanoclusters via the sequential addition of the [Au-9(SR)(3)] unit (i.e., Au-40(SR)(24) + [Au-9(SR)(3)] -> Au-49(SR)(27) + [Au-9(SR)(3)] -> Au-58(SR)(30)). The generic growth pattern underlying this sequence of nanoclusters can be viewed as the sequentially addition of three highly stable tetrahedral Au4 units on the cores. Density functional theory calculations show that the Au-58(SR)(30) nanocluster exhibits the large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMOLUMO) gap and all-positive harmonic vibrational frequency, suggesting its high chemical stability. In addition, gold nanoclusters Au-49(SR)(27) and Au-58(SR)(30) with mix-packed (e.g., face-centered cubic (fcc) and nonfcc) cores have been understood by constructing their isomeric structures, which show that the cores of thiolate-protected gold nanoclusters prefer to adopt close-packed structures.