Tertiary Chiral Nanostructures from C-H...F Directed Assembly of Chiroptical Superatoms

摘要

We report the synthesis and structure of tertiary chiral nanostructures with 100 % optical purity. A novel synthetic strategy, using chiral reducing agent, R and S-BINAPCuBH(4) (BINAP is 2,2 '-Bis(diphenylphosphino)-1,1 '-binaphthyl), is developed to access to atomically precise, intrinsically chiral [Au7Ag6Cu2(R- or S-BINAP)(3)(SCH2Ph)(6)]SbF6 nanoclusters in one-pot synthesis. The clusters represent the first tri-metallic superatoms with inherent chirality and fair stability. Both metal distribution (primary) and ligand arrangement (secondary) of the enantiomers exhibited perfect mirror images, and unprecedentedly, the self-assembly driven by the C-H...F interaction between the phenyl groups of the superatom moieties and SbF6- anions induced the formation of bio-mimic left- and right-handed helices, achieving the tertiary chiral nanostructures. DFT calculations revealed the connections between the molecular details and chiral optical activity.