Molecular tectonics: control of reversible water release in porous charge-assisted H-bonded networks.

The combinations of bisamidium dicationic tectons 1-2H+ and 2-2H+ bearing two OH groups as additional H-bond donor/acceptor sites with M(CN)62 (M = Fe, Co, Cr) anions lead to the formation of robust porous crystals (decomposition temperature in the range of 240-300 degrees C) offering channels occupied by water molecules. The release and uptake of solvent molecules takes place through a reversible single crystal-to-single crystal transformation. Importantly, the temperature of dehydration can be increased by ca 40 degrees C through the decoration of the channels by introduction of OH groups on the backbone of the organic tecton.