Light‐ and Water‐Driven Nanoarchitectonics of Amphiphilic Azobenzene Derivatives: Photoswitching and Self‐Aggregation Dispersion Studies

An aggregation dispersion behavior is studied in UV light and in the presence of water to azobenzene derivatives. The nonfluorinated trans and cis derivative initially appear in the macromolecular aggregated states but the addition of water disperses the solution. However, the fluorinated derivative shows uniform micromolecular aggregated features in the trans state and disperses further after the addition of water.

Herein, how aggregation-dispersion behavior of fluorinated azobenzene derivatives 5 and 6 with an amphiphilic dodecaoctane substituent is affected by UV light irradiation and water is described. The influence of fluorine substituents on their photophysical properties, photoswitching differences, and aggregation in waterin-ground trans and excited cis-state is studied. Their photophysical and photoswitching properties are investigated under the polar MeOH and nonpolar solvent benzene and it is found that 6 shows different behavior as compared to 5 in both solvents. Further, to check their aggregation properties in MeOH, a competing solvent water is added. It is observed that in MeOH–H₂O solution (0.9-1.5 mL), compounds show a redshift with a decrease in the absorbance, and fluorescence emission is found. Further, dynamic light scattering shows the opposite behavior, 5 initially is in the macromolecular aggregated state both in trans and cis-states but the addition of water disperses the solution. However, 6 shows uniform micromolecular aggregated features in the trans-state and disperses further after the addition of water. Scanning electron microscopy images of 5 and 6 suggest aggregated patterns that change the morphology when added to water. IR, ¹H, and ¹⁹F NMR are done to understand the site of aggregation and intermolecular interactions.

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