Pillar[n]arene‐Based Supramolecular Switches in Solution and on Surfaces

Abstract

response to specific physical or chemical stimuli including, but not limited to, pH, light, redox, competitive agents, and tem perature. In particular, pseudorotaxanes, comprising of a rod component without bulky end groups encircled by a wheel entity via noncovalent bonds, can be employed as a superior class of candidates for supramolecular switches. [3] There fore, the study of macrocyclic receptors as the wheel entity of pseudorotaxanes has become one of the research hotspots in the field and received great attention. [4] Following the advance of macrocyclic chemistry based on crown ethers, cyclo dextrins, calixarenes, and cucurbit[n]urils, pillar[n]arenes (n = 5-15), first reported by Ogoshi et al. in 2008, have emerged as a rising star among synthesized macro cycles. [5] Pillar[n]arenes, composed of n hydroquinone units linked by methylene bridges at the 2 and 5positions, pos sess rigid pillarlike molecular structures and πelectron rich hydrophobic cavities that are favorable for the binding of electrondeficient guests. [6] Owing to the highly modi fiable rims of pillar[n]arenes, numerous pillar[n]arene derivatives with diverse functionalities can be facilely obtained either via the cyclization of pretailored 1,4dialkoxybenzene monomers or by postsynthetic modification. [7] The versatile functionalization of pillar[n]arenes beneficially affords their pos sible usages in both organic and aqueous phases, making the host−guest interactions with a large variety of ionic or neutral guests possible. [8] Thus far, pillar[n]arenes and their deriva tives have served as a prominent family of building blocks for the rational creation of supramolecular switches on the basis of the formation of various pseudorotaxanes upon their respon sive complexation with guest entities. [3] Although the dynamic activities of supramolecular switches are generally and fundamentally investigated in solution, growing interest has been focused on the transfer of supra molecular switches from solution phase to more condensed phases, that is, solid surfaces and interfaces. Through the incor poration on rigid solid supports of metal or other inorganic surfaces, the installed switches are able to produce amplified collective switching motions, concurrently modulating the sur face properties and endowing the inherent substrates with valid responses to specific triggers. [2a,9] Hence, the shifting of supra molecular switches from solution to solid surfaces denotes a significant step toward the realization of artificial nanosystems with operationally controllable properties, stimuliresponsive features, and multifunctionalities. The design and synthesis of new synthetic macrocycles has driven the rapid development of supramolecular chemistry and materials. Pillar[n]arenes, as a new type of macrocyclic compounds, are used as a promising type of building blocks for switchable supramolecular systems due to their versatile functionalization and the ability of binding toward various guest molecules. A number of guests can form inclusion complexes with...

Supramolecular Chemistry: Host–Guest Molecular Complexes

“…The water-soluble amino pillar[5]arene functional with Au nanoparticles serves as a fluorescence probe for dopamine determination [ 100 ]. The pillar[n]arene macromolecule shows stable HG supramolecular switches in solution and on surfaces due to their binding ability of various guest molecules and multipurpose, adaptable functionalization [ 101 ]. The photo-responsive composite surface was assembled via adjusting azobenzene-calix[4]arene on a micro-structured silicon substrate using UV light irradiation as a stimulus [ 102 ].…”

Solvent-Driven Chirality Switching of a Pillar[4]arene[1]quinone Having a Chiral Amine-Substituted Quinone Subunit

“…Compared with molecular chirality, the supramolecular chirality is more attractive in terms of their regulatability by the external conditions such as temperature ( Yao et al, 2017 ; Fan et al, 2019 ), pH ( Kanagaraj et al, 2020 ; Liang et al, 2020 ; Hao et al, 2021 ), redox ( Xiao et al, 2020 ), light ( De Poli et al, 2016 ), chemical additives ( Lee et al, 2018 ), pressure ( Yao et al, 2021a ), and solvents ( Borovkov et al, 2003b ; Fan et al, 2019 ). Pillar[n]arenes ( Ogoshi et al, 2008 ; Xue et al, 2012 ; Pan et al, 2015 ; Fan et al, 2016 ; Jie et al, 2018 ; Lv et al, 2018 ; Li G. et al, 2019 ; Xiao et al, 2019 ; Ji et al, 2020a ; Lou and Yang, 2020 ; Mi et al, 2020 ; Liu et al, 2021 ; Peng et al, 2021 ), as a relatively new class of synthetic macrocyclic hosts with some unique properties ( Guo et al, (2018) ; Lai et al, (2019) ; Liu et al, (2019) ; Wang et al, (2021 ), have proved to be an ideal platform to construct unimolecular chirality based on different external stimuli-driven. We have demonstrated that the chirality of pillar[n]arene derivatives could be manipulated by external stimuli, including temperature, redox, light, and pressure ( Yao et al, 2017 ; Xiao et al, 2020 ; Yao et al, 2021a ; Yao et al, 2021b ).…”

Macrocyclic Photoinitiator Based on Prism[5]arene Matching LEDs Light with Low Migration

“…[29,30] Macrocycles have made wide application in many fields, such as ion channels, sensing, molecule adsorption, catalysis, and cancer treatment. [31][32][33][34][35][36][37][38][39][40] In our previous work, macrocyclic pillar [6]arene was first developed as photoinitiators and successfully used for initiating polymerization under the irradiation of mercury lamp light (295 nm). [41] Prismarene is a novel kind of macrocycle whose 2,6-dimethoxynaphthalene units are connected by methylene bridges, which was first synthesized in 2020.…”