Gelation of a highly fluorescent urea-containing triarylamine derivative: N, N, N ′, N ′-tetrakis (p-octadecylureido-phenyl)-p-phenylenediamine in organic solvents

Abstract

An innovative gelator was synthesised by non-covalent interactions from triarylamine derivative as N, N, N′, N′-tetrakis(p-octadecylureido-phenyl)-p-phenylenediamine (TOUPPD), and its gelation potential was examined in different organic solvents. The resulting thermo-reversible gel was characterised by using the dropping ball method and a number of other methods. The melting temperature of the gel increased with the TOUPPD concentration. Temperature-dependent UV–vis and fluorescence analysis revealed that the gel exhibited blue fluorescence and H-aggregation in decalin. Intermolecular hydrogen bonding in the TOUPPD gel was observed from FT-IR spectrometry. The morphological self-assembled feature of the gel was studied by atomic force microscopy (AFM). In conductivity and solid electrolyte experiments, the organogel electrolytes exhibited high conductivity (σ) comparable to the corresponding NaClO₄/THF solution. The conductivity of the gel electrolytes increased with the concentration of the electrolyte salt. The TOUPPD film exhibited well-defined conductivity of 2.5 × 10^–4 to 3.5 × 10^− 6 S cm^− 1 in the solid state upon addition of a known concentration of trifluoroacetic acid (TFA).

Keywords:

• triarylamine
• self-assembled
• aggregation
• supramolecular chemistry