Symmetrical and asymmetrical surface structure expansions of silver nanoclusters with atomic precision.

Controlling symmetrical or asymmetrical growth has allowed a series of novel nanomaterials with prominent physicochemical properties to be produced. However, precise and continuous size growth based on a preserved template has long been a challenging pursuit, yet little has been achieved in terms of manipulation at the atomic level. Here, a correlated silver cluster series has been established, enabling atomically precise manipulation of symmetrical and asymmetrical surface structure expansions of metal nanoclusters. Specifically, the -axisymmetric Ag(BDTA)(PPh) nanocluster underwent symmetrical and asymmetrical surface structure expansions an acid-mediated synthetic procedure, giving rise to -axisymmetric Ag(BDTA)(PPh) and -axisymmetric Ag(BDTA)(PPh), respectively. In addition, structural transformations, including structural degradation from Ag to Ag and asymmetrical structural expansion from Ag to Ag, were rationalized theoretically. More importantly, the asymmetrically structured Ag nanoclusters followed a chiral crystallization mode, and their crystals displayed high optical activity, derived from CD and CPL characterization. This work not only provides an important model for unlocking the symmetrical/asymmetrical size growth mechanism at the atomic level but also pioneers a promising approach to activate the optical activity of cluster-based nanomaterials.