摘要
Pillar[5]arene-based molecular universal joints(MUJs), bearing fused crown ether subring(MUJ1 and MUJ3) or a ring without ether oxygen atom(MUJ2), were synthesized and enantio–differentiated. Significant chiral inversion was observed for the crown ether-fused MUJs upon the addition of equivalent cations Na+, showing an anisotropy(g) factor of 0.014, while alkyl subring-fused MUJ2 showed no CD inversions. Unprecedentedly, sodium ion triggered rolling-in motion of the subring to the pillar[5]arene cavity was verified, and the synergistic noncovalent interaction of cation-π interactions and C–H···π interactions were responsible for the stabilized self-included conformers. The addition of Me OH or competitive hosts 15-crown-5 ether disassembled the complex of MUJ1 and Na+followed by a rolling-out of the subring, which made the sodium-ion triggered chiroptical switching reversible.
基金
the support of this work by the National Natural Science Foundation of China (Nos. 22171194, 21971169, 92056116, 21871194)
the Science & Technology Department of Sichuan Province (Nos. 2022YFH0095, 2021ZYD0052)。
