Diastereoselective Supramolecular Encapsulation and Chirality Transfer Between Cholesteryl Binaphthyl Conjugates and Polyaromatic Hydrocarbon.

Abstract

Diastereoselective effect plays an important role in the synthesis of chiral complexes and macrocyclic compounds, while its function in selective coassembly and chirality transfer has yet to be unveiled. In this work, two pairs of diastereomers containing R/S- binaphthyl and homochiral cholesteryl domains are synthesized, which provide multiple sites to encapsulate polyaromatic hydrocarbon through π-π and CH-π interactions. X-ray structures and computational studies suggest the binaphthol derivatives feature CH-π folding into butterfly-like open geometry, while binaphthylenediamine derivatives adopt closed geometry supported by van der Waals between cholesteryl domains. Driven by solvophobic forces, the building units self-assemble into vesicles and nanofibers in the aqueous and methanol phases, respectively. Binaphthol derivatives selectively encapsulate pyrene by naphthalene domains in the vesicle phase, while binaphthylenediamine derivatives encapsulate pyrene by cholesteryl domains in the nanofiber phase. Density functional theory-based calculations and circular dichroism spectra evidence the closed geometry of binaphthylenediamine derivatives facilitates a clamp-type host to increase the affinity toward pyrene in spite of the strong solvation competition. This work unveils the diastereoselectivity in the chiral coassembly, deepening the understanding of the precise synthesis of functional chiroptical complexes.