Construction of Photoreactive Chiral Metal-Organic Frameworks and Their [2 + 2] Photocycloaddition Reactions.

Chiral metal-organic frameworks (CMOFs) and solid-state [2 + 2] photocyclization have been explored as independent areas in crystal engineering. We herein report the photoreactive CMOFs that undergo a [2 + 2] photocycloaddition reaction for the first time. Through the incorporation of a dipyridyl olefin ligand, 1,4-bis[2-(4-pyridyl)ethenyl]benzene, and d-camphoric acid or l-camphoric acid, we constructed a pair of homochiral Zn(II) CMOFs (d- 1 or l- 1 ) with a two-dimensional sql topology via a two-step procedure to avoid racemization. Both d- 1 and l- 1 were photoinert due to the large olefin bond separation. The removal of the solvent molecules between layers enabled them (d- 1a and l- 1a ) to undergo [2 + 2] cycloaddition reactions; d- 1a is more reactive (70%) than l- 1a (20%) probably due to proper desolvation-induced rearrangement. The photoluminescence properties are also discussed. This work presents a new perspective on photoreactive homochiral network materials with diverse topologies and applications.