A curved host and second guest cooperatively inhibit the dynamic motion of corannulene

Yang Yang,Tanya K Ronson,Jieyu Zheng,Alexandre Martinez,Zifei Lu,Nicolas Vanthuyne,Jonathan R Nitschke

doi:10.1038/s41467-021-24344-w

Abstract

Biomolecular systems show how host–guest binding can induce changes in molecular behavior, which in turn impact the functions of the system. Here we report an artificial host–guest system where dynamic adaptation during guest binding alters both host conformation and guest dynamics. The self-assembled cage host employed here possesses concave walls and a chirotopic cavity. Complementarity between the curved surfaces of fullerenes and the inner surface of the host cavity leads the host to reconfigure stereochemically in order to bind these guests optimally. The curved molecule corannulene undergoes rapid bowl-to-bowl inversion at room temperature. Its inversion barrier is increased upon binding, however, and increased further upon formation of a ternary complex, where corannulene and a cycloalkane are both bound together. The chiral nature of the host also leads to clear differences in the NMR spectra of ternary complexes involving corannulene and one or the other enantiomer of a chiral guest, which enables the determination of enantiomeric excess by NMR.

Highlights

Biomolecular systems show how host–guest binding can induce changes in molecular behavior, which in turn impact the functions of the system
The conformations and shapes of biomacromolecules can change to fit the target substrate, in a process known as induced fit[1], or an auxiliary substance may bind to a host–guest complex to form a ternary complex, regulating or modulating the initial interaction[2]
Artificial molecular systems that mimic the sophisticated processes of induced fit and property regulation via ternary complex formation are challenging to design, but important in producing complex and functional systems of molecules[3,4,5], and in understanding the molecular basis of binding in relevant biological processes

Summary

Introduction

Biomolecular systems show how host–guest binding can induce changes in molecular behavior, which in turn impact the functions of the system. Within the chirotopic[39] cavity of 1, the local symmetry of encapsulated C70 is broken from D5h to D5, resulting in the splitting of its two highest-intensity 13C NMR peaks into two sets of signals (Supplementary Fig. 26)[40]. The differences in size and chirality between the empty host and host–guest complexes illustrate that the cages can reconfigure stereochemically to adapt to large guests with curved surfaces.

Results

Conclusion