From Mechanically Interlocked Structures to Host-Guest Chemistry Based on Twisted Dimeric Architectures by Adjusting Space Constraints

Mechanically interlocked molecules (MIMs) and host-guest chemistry have received great attention in the past few decades. However, it remains challenging to design architectures with mechanically interlocked features and construct cavities for guest molecule recognition using similar building blocks. In this study, we designed and constructed a series of novel twisted supramolecular structures by assembling various multitopic terpyridine (tpy) ligands with the same diameter and Zn(II) ions. The obtained complexes exhibited evolutional architectures and showed distinctively different space-constraint effects. Specifically, the assembled dimer SA, SB, and SBH displayed mechanically interlocked phenomena, including [2]catenane and [3]catenane, with an increase in concentration. However, no interlocked structures were observed in complexes SC and SCH constructed by hexatopic tpy ligands due to the significant space constraints. The single-crystal data of complex SCH further proved significant space constraints and illustrated the formation of a relatively closed cavity, which showed excellent host-guest properties for different calixarenes, especially high affinity for calix[6]arene. [GRAPHICS]

Automated summary

In this study, a series of novel twisted supramolecular structures were designed and constructed using various multitopic terpyridine ligands and zinc ions. The space-constraint effects and mechanically interlocked phenomena of these structures were investigated.