Abstract

Distinct dynamics and stimuli-responsiveness of two hetero[4]rotaxanes incorporating mechanically interlocked cucurbit[6]uril (CB[6]) and cyclodextrin (β-CD or γ-CD) were investigated.1 Although the two rotaxanes are structurally differentiated by a subtle variation, which is a sugar unit only, the relative interaction strength between different interlocked components (the CD, CB[6], biphenyl station, ammonium unit, tetra(ethylene glycol) linker) are amplified. Thus, very distinctive shuttling performances of the CDs along the axle of two [4]rotaxanes were revealed by NMR studies, and the co-conformational changes can be manipulated by their responsiveness towards temperature, solvent polarity, pH, and external guests.

Reference:

1. Deng, Y.; Ren, X.; Tang, M. P.; Lai, S. K.-M.; Ng, A. W. H.; Li, C.-N.; Au-Yeung, H. Y. Mater. Today Chem., 2022, 24, 100952.