Controlling luminescent and thermoresponsive materials with molecular photoswitching

Molecular switching motifs based on dithienylethenes provide a versatile framework for developing materials whose properties can be toggled between two states by alternately exposing them to ultraviolet and visible light. Materials with these features can then be selectively addressed and their properties manipulated even when present in complex mixtures, making them attractive for applications in controlled drug delivery, catalysis and imaging. Developing these materials nevertheless requires design strategies that couple light-induced changes in the dithienylethene architecture to desirable secondary events (e.g. changes in catalytic or biological activity, refractive index, or electrical resistance). This thesis describes analogous design strategies developed to control luminescent and thermoresponsive materials using optical cues. In the first system, quantum dot luminescence is reversibly quenched by photoisomerization of a cationic dithienylethene ligand. In the second, photoisomerization of a bicyclic dithienylfuran adduct is shown to gate the reversibility of the Diels-Alder reaction at elevated temperatures.