Pillar[5]arene Based Pseudo[1]rotaxane Operating as Acid/Base‐Controllable Two State Molecular Shuttle

Abstract

A ethylene glycol bridged pyridine and pillar[5]arene based mechanically selflocked pseudo[1]rotaxane was constructed successfully. The structure and selflocked conformation of pseudo[1]rotaxane were confirmed by 1H, 2D NMR spectrum and HR‐ESI‐MS. It was found that in dilute solution the pseudo[1]rotaxane could be operated as an acid/base‐controllable two state molecular shuttle while In concentrated solution, the pseudo[1]rotaxane existed as a dimer and could be operated from shrinking state to extension state.

Concentration-dependent supramolecular self-assembly of A1/A2-asymmetric-difunctionalized pillar[5]arene

“… 15 More recent, concentration dependence nature between the formation of pseudo[1]rotaxane and interlocked-dimer was also been demonstrated using pillar[5]arene bearing ethylene glycol bridged pyridine, in addition to the acid/base control of the dimer between the shrinking state to extension state. 16 …”

Stimuli-Responsive Internally Ion-Paired Supramolecular Polymer Based on a Bis-pillar[5]arene Dicarboxylic Acid Monomer

“…Water-soluble AB-type PSPs can easily be obtained by decorating the two rims of the pillararene monomer with positively 11 or negatively 12 charged moieties. However, attachment of a suitable guest component to a pillararene macrocycle does not always deliver PSPs but occasionally results in the competitive formation of [c2]daisy chain dimers 13 or [1]rotaxanes 14 (as a result of self-inclusion). Very recently, an unusual linear AA-type PSP composed of a repeating decamethoxy-pillar[5]arene/1,4-dibromobutane pseudorotaxane held together by guest Br–Br interactions has been described.…”

Noncovalently bound and mechanically interlocked systems using pillar[n]arenes

“…19). 126 In solution, the equilibrium favouring dimeric species could be modified by changing the solvent and temperature, and by adding competitive guests and hydrogen-bonding molecules. 155,156 The assembly/disassembly behaviour was coupled with fluorescence response using a pillar [5]arene bearing A1-anthracene-and A2-ammonium-terminated side chains (P64).…”

“…Without capping, similar shuttling-induced molecular extension was realized with (P36) 2 by protonation of the pyridine ends in response to TFA. 126 The dimeric assemblies introduced above are sometimes known as [c2]daisy chains. Two threading side chains in a [c2]daisy chain can be connected to form another macrocycle.…”