Tuning Luminescence and Photoreactivity in Organic Co-crystals and Salts

Molecular crystal engineering, i.e. the design and synthesis of solid state molecular materials with predefined properties, is used here to exploit non-covalent interactions to pre-arrange building blocks (see Figure 1) in their crystalline state for properties modification and specific applications, all involving the absorption of UV radiation. Depending on the chemical complexity and/or application, crystals of appropriate size and purity are required for characterization, chemical reactivity and applicative processes. Examples will be presented; among them: (i) single crystal to single crystal photodimerization; (ii) co-crystallization as a tool to switch from fluorescence to phosphorescence in the solid state.