Solvent‐Induced Self‐Assembly of Naphthalenediimide Conjugated to Tetraphenylethene through D‐ and L‐Alanine

Abstract

Herein, the synthesis and supramolecular self‐assembly of naphthalenediimide (NDI)‐tetraphenylethene (TPE) conjugates with l‐alanine (coded as: 1) and d‐alanine (coded as: 2) was investigated. The pair stereoisomer molecules were designed to undergo self‐assembly under solvophobic effects. Mixtures of THF–water was used to fine tune the solvophobic effect leading to microbelt for both 1 and 2 in 40% v/v of THF in H2O, while microbelt and particulate microsphere supramolecular structures were observed in 20%, v/v THF in H2O. When 10% THF in H2O was employed derivative 1 produces belt‐like structures, however, 2 produces microsphere. Less uniformly defined microstructure morphologies of 1 and 2 were formed in THF/hexane and DCM/hexane. The solvophobic effect on self‐assembly further evidenced using UV/Vis, fluorescence, circular dichroism, X‐ray diffraction (XRD) spectroscopies. DLS used to evaluate formation of assembly in solution, DFT (density functional theory) and TD‐DFT (time dependent density functional theory) molecular modelling support the hypothesis. Scanning electron microscopy used to visualise formation of supramolecular self‐assembled nano‐ and micro‐structures.

Synthesis and self-assembly of a diphenylalanine–tetraphenylethylene hybrid monomer and RAFT polymers with aggregation-induced emission

“…The combination of AIE molecules with self-assembling motifs via molecular modifications is promising in the fabrication of nano-and microstructures with tunable size/shape and fluorescent properties, which have great potential for applications in devices and sensors. [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] Several synthetic approaches have been developed, which include the chemical linkage of AIE molecules with self-assembling motifs, [31][32][33][34][35][36][37][38][39][40][41] conjugation with chiral polymers, [42][43][44] and co-assembly of AIE molecules and self-assembling motifs. 45,46 The synthesized structures are mainly constructed via non-covalent bonds such as hydrogen bonding and hydrophobic and electrostatic interactions.…”

“…45,46 The synthesized structures are mainly constructed via non-covalent bonds such as hydrogen bonding and hydrophobic and electrostatic interactions. [32][33][34][35][36][37][39][40][41][43][44][45][46] As a self-assembling motif, TPE molecules hybridized with amino acids or peptides show the ability to self-assemble into various structures, such as spheres, vesicles, and helical nano-and microfibers, which is achieved through specific interactions derived from amino acids or peptides. 32,33,40,41 These hybrid materials also exhibit aggregation-induced circular dichroism (AICD) 32,33,43,44 and circularly polarized luminescence due to the transfer of chirality by amino acids to achiral AIE molecules.…”

“…32,33,40,41 These hybrid materials also exhibit aggregation-induced circular dichroism (AICD) 32,33,43,44 and circularly polarized luminescence due to the transfer of chirality by amino acids to achiral AIE molecules. [32][33][34][35][36][37][39][40][41]43,44 Herein, we report the synthesis, self-assembly, and polymerization of a diphenylalanine-TPE hybrid monomer (APhePheTPE) consisting of diphenylalanine as the self-assembling motif and TPE as an AIE luminogen (AIEgen). Diphenylalanine-containing acrylamide (APhePheOH) bearing a carboxylic acid was combined with the TPE derivative (TPEOH) via condensation to afford a hybrid monomer (APhePheTPE), which was used for the controlled synthesis of the hybrid homopolymer (PAPhePheTPE), as shown in Scheme 1.…”

Solvent-Directed Transformation of the Self-assembly and Optical Property of a Peptide-Appended Core-Substituted Naphthelenediimide and Selective Detection of Nitrite Ions in an Aqueous Medium

“…The amino acid/peptide-conjugated NDIs selfassemble using π−π interaction, hydrogen bonding interaction, and van der Waals interactions to form aggregates or gels in different solvent systems. 28,30−32 Some common factors such as the nature of the solvent, 47 pH of the medium, 48 and nature of the substituent 49 can influence the self-assembly of these types of molecules. The π-conjugated organic molecules selfassemble mainly in two different ways: "face-to-face" stacking or H aggregates and "edge-to-edge" stacking or J aggregates.…”

“…The self-assembling nature of NDIs is the most important characteristic and they have the capability to form various well-defined self-organized nanostructures like a nanofiber, nanotube, nanoribbon, nanosheet, and nanocylinder with tunable properties. ,, To study the self-assembly of NDIs in different solvent systems, amino acids and a variety of synthetic peptides can be substituted at the periphery of NDI. − The usefulness of amino acids/peptides − arises not only due to their hydrogen bonding interaction among the amide (CO–NH) groups but also due to their biocompatible and biodegradable nature. The amino acid/peptide-conjugated NDIs self-assemble using π–π interaction, hydrogen bonding interaction, and van der Waals interactions to form aggregates or gels in different solvent systems. ,− Some common factors such as the nature of the solvent, pH of the medium, and nature of the substituent can influence the self-assembly of these types of molecules. The π-conjugated organic molecules self-assemble mainly in two different ways: “face-to-face” stacking or H aggregates and “edge-to-edge” stacking or J aggregates .…”