Reversible structural switching of a metal-organic framework by photoirradiation.

A photoresponsive metal organic framework material undergoes switching of its pore volume and sorption capacity. UV irradiation of the crystals causes cyclisation within the bis-thienylcyclopentene bridging ligands, thereby altering the node positions relative to one another along the Zn-L-Zn linkages. Incorporation of conformational flexibility into the dicarboxylic acid co-ligands facilitates the change in the framework geometry enforced by photocyclisation.