• Light-controlled self-assembly of non-photoresponsive nanoparticles Link

Nature Chem. 2015, 7, 646-652

Organic molecular switches namely, protonated-merocyanine was shown to modify the pH of a methanolic medium reversibly when exposed to visible light on or off - in such a way that the nanoparticles which do not respond to external stimuli such as light undergo self-assemble / deassemble process in a reversible fashion depending on the state of the external switch. Performing the assembly process in thin films of gels allowed us to draw images that spontaneously disappeared after a specific period of time.

• Nanoporous frameworks exhibiting multiple stimuli responsiveness Link

Nature Commun. 2014, 5, 3588

Majority of organic molecular switches require conformational freedom to isomerize, and therefore, switching in the solid state is prohibited. Here we describe two families of nanoporous materials incorporating the spiropyran molecular switch. These materials exhibit a variety of interesting properties, including reversible photo-chromism and acidochromism, light-controlled capture and release of metal ions, as well reversible chromism induced by solvation/desolvation.

• Cyclic kinetics during thermal equilibration of an axially chiral bis-spiropyran Link

J. Am. Chem. Soc. 2014, 136, 11276–11279

A compound combining the features of a molecular rotor and a photoswitch was synthesized and was shown to exist as three diastereomers, which interconvert via a reversible cyclic reaction scheme. Each of the three diastereomers was isolated, and by following the equilibration kinetics, activation barriers for all reaction were calculated. The results indicate that the properties of molecular switches depend heavily on their immediate chemical environment. The conclusions are important in the context of designing new switchable molecules and materials.