Self-Assembly Tuning of α-Cyanostilbene Fluorogens: Aggregates to Nanostructures

Two AIE active alpha-cyanostilbene fluorophores substituted with octyl and hexadecyl chains were synthesized and examined for their absorption and fluorescence properties. The alkoxy substitution tunes the self-assembly in water and exhibits an intensity enhanced bathochromic shift, resulting in well-defined nanospheres with the formation of nice dendrimeric structures. Monte Carlo simulations validate our experimental observations and show the greater propensity of self-assembly formation for cyanostilbene containing a hexadecyl chain compared to a derivative containing an octyl chain. The results are substantiated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and dynamic light scattering (DLS) studies. Such tunable self-assembled nanostructures seem promising for material and biological applications.