Amphiphilic Schiff Base Organogels: Metal‐Ion‐Mediated Chiral Twists and Chiral Recognition

Abstract

New amphiphilic gelators that contained both Schiff base and L-glutamide moieties, abbreviated as o-SLG and p-SLG, were synthesized and their self-assembly in various organic solvents in the absence and presence of metal ions was investigated. Gelation test revealed that o-SLG formed a thermotropic gel in many organic solvents, whilst p-SLG did not. When metal ions, such as Cu(2+), Zn(2+), Mg(2+), Ni(2+), were added, different behaviors were observed. The addition of Cu(2+) induced p-SLG to from an organogel. In the case of o-SLG, the addition of Cu(2+) and Mg(2+) ions maintained the gelating ability of the compound, whilst Zn(2+) and Ni(2+) ions destroyed the gel. In addition, the introduction of Cu(2+) ions caused the nanofiber gel to perform a chiral twist, whilst the Mg(2+) ions enhanced the fluorescence of the gel. More interestingly, the Mg(2+)-ion-mediated organogel showed differences in the fluorescence quenching by D- and L-tartaric acid, thus showing a chiral recognition ability.

Gels with sense: supramolecular materials that respond to heat, light and sound

“…For instance, Jin et al found that copper(II) can interact with a non-gelating anil to form gels, while inducing a gelating analogue to form twisted, chiral fibres rather than the usual linear aggregates. 329 It is clear that functionalities capable of intramolecular proton transfer may confer responsiveness to a range of chemical and physical stimuli. However, where switching must substantially alter the mechanical properties of a material, groups that can undergo larger structural changes are usually better suited to the task.…”

Enantioselective Light Harvesting with Perylenediimide Guests on Self‐Assembled Chiral Naphthalenediimide Nanofibers

“…[2d, [8][9][10] Ther ecognition of chiral analytes by chiral molecular systems can be detected through changes in the optical spectra. [14][15][16][17][18][19] This amplified output makes the analyte detection possible at submicromolar to picomolar concentrations.Herein, we demonstrate the use of achiral nanofiber platform, obtained through the self-assembly of ac hiral bichromophoric naphthalenediimide (NDI) derivative,f or the absolute enantiomeric recognition of ap erylenediimide (PDI) based guest molecule.The chiral bichromophoric NDI derivatives self-assembled into nanofibers in am ethylcyclohexane (MCH) rich solution, exhibiting intense blue-green emission and acertain degree of CPL. [11] In contrast, the chiral response of supramolecular systems [3,[11][12][13] is often more sensitive owing to signal amplification.…”

A silver-induced metal-organic gel based on biscarboxyl-functionalised benzimidazole derivative: stimuli responsive and dye sorption

“…Show good properties in gelating with metal ions actions and van der Waals interactions, play an important (29)(30)(31). For instance, the terpyridyl-based ligands have role in self-assembling LMWGs to form entangled been effectively shown to form gels with platinum salts nanostructures (3,4). Recently, LMWGs have received and their photophysical properties were investigated.…”