Structure and Electronic Structure Evolution of Thiolate-Protected Gold Nanoclusters Containing Quasi Face-Centered-Cubic Kernels

A structure evolution map of face-centered cubic (fcc)-structured thiolateligand protected gold nanoclusters is outlined on the basis of total structure determination of a new 6e Au-21(SR)(15) (R = tert-butyl, t-Bu) cluster. The structural evolution map described some basic structural evolution patterns such as a triangle-Au-3 and tetrahedron-Au-4 associated gold-core evolution pattern and the periodic or symmetric growth of gold cores and ligand shells. According to the structural evolution map, a topological structure electronic structure relationship is also proposed. The delocalized valence electronic properties of any fcc-structured gold clusters may be expressed as the linear combinations of the molecular orbitals of the fragment 2e units (Au3+ and Au-4(2+)). The structural disciplines and topological structure electronic structure relationships reported in this work laid a basis for understanding the structural evolution and electronic structure of fcc-structured thiolate-protected gold nanoclusters. Particularly, the established structural evolution map provides a tool to explore new magic-sized clusters and cluster structures. In this work, a new fcc-structured 4e Au-17(SR)(13) and a new isomer structure of the 8e Au-28(SR)(20) cluster were predicted. The medium-sized fcc-structured gold clusters locating in the size range from 52 to 92 gold atoms and even larger-sized gold clusters can be also explored from the structural regularities described in the map.