Balancing ring and stopper group size to control the stability of doubly threaded [3]rotaxanes

Abstract

The kinetic stability of a series of doubly threaded [3]rotaxanes with differing ring and stopper size was examined.

A molecular sheaf: doubly threaded [6]rotaxane

“…So far, it has still been challenging to achieve a doubly threaded rotaxane with such a high yield and selectivity. 6 d ,19 Despite the fact that the 5 : 2 complex appears almost as the sole component at the ratio of 6 : 2 in the ESI-HRMS spectra (Fig. S36, ESI†), even in the presence of large excess amounts of 1a , [7]rotaxane was not isolated, and the separation only offered the doubly threaded [6]rotaxane (Table 1).…”

Tuning Stopper Size in Multiresponsive [2]Rotaxanes for Fluoride Anion Selective Metastability

“…Metastability was also observed in a [2]rotaxane composed of a 4-tertbutylphenyl end group with macrocycles BMP25C8 (benzometaphenylene[25]crown-8) and DB24C8 . Surprisingly, a [2]rotaxane interlocked with a smaller [22]crown-6 ether exhibited metastability with an unsubstituted benzene end group. , Recently, doubly threaded [3]rotaxanes incorporating large ditopic 44–46 atom macrocycles were reported to exhibit metastability …”