Recent Applications of Pillar[n]arene-Based Host–Guest Recognition in Chemosensing and Imaging

Abstract

Pillar­[n]­arene is a novel kind of synthetic supramolecular macrocyclic host characterized by its particular pillar-shaped structure consisting of an electron-rich cavity and two finely adjustable rims. Benefiting from its rigid structure, facile synthesis, ease of functionalization, and outstanding host–guest chemistry, pillar­[n]­arene shows great potential for diverse applications. Significantly, the host–guest recognition of pillar­[n]­arene provides a novel approach for chemosensing and imaging. Herein, this Review critically and comprehensively reviews the applications of pillar­[n]­arene-based host–guest recognition in chemosensing and imaging. The sensing and imaging mechanisms as well as the unique roles and advantages of pillar­[n]­arene-based host–guest recognition are summarized. In addition, preparations of hybrid materials based on pillar­[n]­arene and inorganic materials are also introduced comprehensively in the light of chemosensing and imaging. Finally, current challenges and perspectives on pillar­[n]­arene-based host–guest recognition in chemosensing and imaging are outlined.

Supramolecular Assembly‐Induced Emission Enhancement Vesicles Regulated by Pincer‐Like Hosts Containing Pillar[5]arenes

“…in 2008 was regard as a typical type of macrocycles in the construction of supramolecular luminescent materials due to their a) high binding affinity toward electron‐deficient group in organic/aqueous solution; b) high synthetic yield and simple process for further functionalization; c) symmetrical rigid column structure. [ 39–42 ] For instance, the emission intensity of supramolecular polymer networks constructed by tetraphenylethene (TPE)‐based guest moieties tetramer and polymer host materials with pillar[5]arene units dangling at side chains could be enhanced approximate 117‐fold, [ 43 ] moreover, supramolecular gels with enhanced fluorescence intensity could be elegantly constructed by employing tetrameric pillar[5]arene containing TPE and neutral guest linker. [ 44 ] In addition, host–guest AIE systems based on pillar[n]arene units have shown extensive application in aqueous solution including sensors, [ 45–50 ] artificial light‐harvesting systems, [ 51 ] photodynamic therapy and bioimaging, [ 52–54 ] etc.…”

“…[38] In particular, pillar[5]arenes reported by Ogoshi et al in 2008 was regard as a typical type of macrocycles in the construction of supramolecular luminescent materials due to their a) high binding affinity toward electron-deficient group in organic/ aqueous solution; b) high synthetic yield and simple process for further functionalization; c) symmetrical rigid column structure. [39][40][41][42] For instance, the emission intensity of supramolecular polymer networks constructed by tetraphenylethene Supramolecular assembly-induced emission enhancement (SAIEE) systems have been proved to be a highly efficient approach for the fabrication of luminescent nanoparticles with uniform morphology. Herein, fluorescent supramolecular vesicles are constructed from tetraphenylethene-based cyano-alkane tetramer (TPE-(CN) 4 ) and pincer-like hosts containing two pillar[5]arene units (B-(TAP[5]A) 2 ) through a synergistic effect of host-guest interactions and hydrophobic interactions.…”

Host–guest sensing towards sodium cyclamate based on a cationic pillar[6]arene reduced graphene nano-composite

“…[22][23][24][25] However, versus other conventional macrocyclic hosts, pillar [n] arenes have important properties such as strong bonding guest and high selectivity in host-guest recognition, which have special recognition capabilities in the sensing area. [26][27][28][29] In recent years, some studies have reported fluorescent sensors by combining the outstanding fluorescence quenching ability of graphene [30][31][32][33] and excellent supramolecular recognition efficiency of pillar[n]arenes. [34][35][36][37] Therefore, in light of these significant findings, we develop a highly selective and sensitive fluorescent sensing platform for SC detection based on a cationic pillar [6]arene (CP6)-functionalized reduced graphene (RGO) nano-composite (CP6-RGO) as a receptor and probe rhodamine B (RB) and the sensing system is shown in Scheme 1.…”

“…22–25 However, versus other conventional macrocyclic hosts, pillar[ n ]arenes have important properties such as strong bonding guest and high selectivity in host–guest recognition, which have special recognition capabilities in the sensing area. 26–29…”

Chiral pillar[5]arene-functionalized silica microspheres: synthesis, characterization and enantiomer separation

“…So far, pillar[5]arene bonded microspheres have also been successfully applied in the field of achiral chromatography separation, including capillary gas chromatography with high resolving capability for a wide range of positional and structural isomers, 29 basic/acidic compounds, 30 or high-performance liquid chromatography for effectively isolating polycyclic aromatic hydrocarbons, xylene isomers, 31 mixed peptide samples, 32 and aromatic positional isomers, 33 due to the accommodation of multiple analytes that act as guest molecules within the cavity through host–guest recognition accompanied by distinct optical signal changes. 34 However, chiral stationary phases prepared from pillar[5]arene-based microspheres have not yet been reported.…”