Accumulation of versatile iodine species by a porous hydrogen-bonding Cu(ii) coordination framework

A microporous coordination framework formed by hydrogen-bonding directed assembly of Cu(II) hexanuclear rings can act as a host for iodine accumulation in an aqueous solution. Various iodine species, I−, I3− or I2, are able to be trapped in the hydrophilic voids of the crystals via a single-crystal-to-single-crystal ion-exchange process. The chemical nature of the iodine species encapsulated inside the coordination framework have been established by single crystal and powder XRD, IR, XPS, EA, TG and iodometric methods. Furthermore, the accumulated iodine species can be easily extracted from the crystals by organic solvents. The kinetics of I3− release from the crystals by extraction with ethanol has been studied.