Photoswitching, colloidal stability, and reversible self-assembly of gold nanoparticles covered with thiolated donor-acceptor stenhouse adducts

Abstract

The possibility of incorporating functional groups into molecular photoswitches is a prerequisite for their versatility and broad-range applications. Herein, we present the first successful synthesis of donor-acceptor Stenhouse adducts (DASA) chromophores featuring a thiol group. The latter provides a unique opportunity to investigate the photoswitching behavior of these visible-light operating chromophores on the surface of metallic nanoparticles. This behavior can be modulated by irradiation time, solvent composition, DASA population, and the organic layer underneath the chromophore. Moreover, the changes in polarity induced by DASA photoisomerization are translated onto the colloidal particles, giving rise to unusual interfacial and bulk-phase phenomena, including nonlinear solubility effects and reversible agglomeration that takes place in a time-controllable manner. These findings pave the way for the rational design of new photoresponsive and smart materials.