Chiral Gold Clusters with Crosslinking Ligands: Geometric Structures and Chiroptical Activities

The geometric diversity of ligand-protected metal clusters has greatly provoked the interest in the chirality of gold clusters bearing crosslinking ligands, which are a subject of active investigations. This review introduces recent geometric and computational studies on chiral gold clusters whose metal core is covered by intramolecular crosslinking moieties. Following an overview of the structural constructions, the geometric features of the ligand shells and metal cores of chiral gold clusters are elucidated, where an emphasis is placed on the importance of helical patterns of the crosslinking ligands arranged around the gold cores. In addition, insights into the atomic-level origin of chiroptical activity, which cannot be accessed solely through experiments, are presented from computational studies using numerical and theoretical approaches, thereby providing a novel methodology based on transition-moment and transition-density analyses.