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
thiolate-ligand protected gold nanoclusters is outlined on the basis
of total structure determination of a new 6e Au21(SR)15 (R = tert-butyl, t-Bu)
cluster. The structural evolution map described some basic structural
evolution patterns such as a triangle-Au3 and tetrahedron-Au4 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 Au42+). 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 Au17(SR)13 and a new isomer structure of
the 8e Au28(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.