Chiral Ligand‐Concentration Mediating Asymmetric Transformations of Silver Clusters: NIR‐II Circularly Polarized Phosphorescence Lighting

Abstract

Near infrared (NIR) emitter with circularly polarized phosphorescence (CPP), known as NIR CPP, has emerged as a key part in the research of cutting‐edge luminescent materials. However, it remains a challenge to obtain nanoclusters with NIR CPP activity. Here, we propose an asymmetric transformation approach to efficiently synthesize two pairs of chiral silver nanoclusters (R/S‐Ag29 and R/S‐Ag16) using an achiral Ag10 nanocluster as starting material in the presence of different concentration chiral inducer (R/S)‐1,1'‐binaphthyl‐2,2'‐diyl hydrogenphosphate (R/S‐BNP). R/S‐Ag29, formed in the low‐concentration R/S‐BNP, exhibits a unique kernel‐shell structure consisting of a distorted Ag13 icosahedron and an integrated cage‐like organometallic shell with a C3 symmetry, and possesses a superatomic 6‐electron configuration (1S2ǀ1P4). By contrast, R/S‐Ag16, formed in the high‐concentration R/S‐BNP, features a sandwich‐like pentagram with AgI‐pure kernel. Profiting from the hierarchically chiral structures and superatomic kernel‐dominated phosphorescence, R/S‐Ag29 exhibits infrequent CPP activity in the second near‐infrared (975 nm) region, being the first instance of NIR‐II CPP observed among CPL metal nanoclusters. This study presents a new approach to reduce the difficulty of de novo synthesis for chiral silver nanomaterials, and facilitates the design of CPP‐active superatomic nanoclusters in NIR region.