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

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.