Superatomic Au25(SC2H5)18 Nanocluster under Pressure

The last decade has witnessed significant advances in the synthesis and structure determination of atomically precise metal nanoclusters. However, little is known about the condensed matter properties of these nanosized metal nanoclusters packed in a crystal lattice under high pressure. Here using density function theory calculations, we simulate the crystal of a representative superatomic gold cluster, [Au25(SR)18]0 (R = C2H5), under various pressures. At ambient conditions, [Au25(SC2H5)18]0 clusters are packed in a crystal via dispersion interactions; being a 7e superatom, each cluster carries a magnetic moment of 1μB or one unpaired electron. Upon increasing compression (from 10 to 110 GPa), we observe the formation of inter-cluster Au-Au, Au-S, and S-S covalent bonds between staple motifs, thereby linking the clusters into a network. The pressure-induced structural change is accompanied by the vanishment of the magnetic moment and the semiconductor-to-metal transition. Our work shows that subjecting crystals of atomically precise metal nanoclusters to high pressures could lead to new crystalline states and physical properties.