Manipulating the physical properties of solid matter using only photons is a major challenge in materials science. In this study, we present the photochemistry occurring in a single crystal of a simpl...

The supra­molecular assemblies in two benzamide-based derivatives are stabilized by inter­molecular hy­dro­gen bonding between the amide groups. Strong directional connectivity provided by hy­dro­gen bonds joins mol­ecules into one-dimensional chains. Thermal analysis allowed us to propose a mechanism for the transformations of one of the derivatives on heating, including exothermic polymerization, amide-group abstraction and partial benzene abstraction.

Expanding the boundaries of synthetic tractability ─ of what molecules can be synthesized and isolated ─ is an eternal challenge for synthetic chemists. The development of new synthetic methods and strategies enables the properties and potential functions of novel molecular targets to be experimentally evaluated. In the context of catalysis, predictable synthetic strategies are often available to access kinetically persistent intermediates such as catalyst resting states. In contrast, synthesis and characterization of the reactive intermediates are often not possible due to the fleeting lifetimes of these species. In crystallo photochemistry combines single-crystal matrix isolation with cryogenic photochemistry to enable reactive intermediates to be synthesized under conditions in which they are persistent and can be (crystallographically) characterized. This Outlook highlights key achievements of in crystallo photochemistry as well as discusses opportunities and challenges that confront realization of the potential of in crystallo synthesis to redefine the boundaries of synthetic tractability.