The study of nanoporous cubic crystals derived from phthalocyanine.

We have discovered that a simple derivative of phthalocyanine (2,3,9,10,16,17,23,24-octa(2',6'-di-iso-propylphenoxy)phthalocyanine) forms cubic crystals which contain interconnected, solvent-filled voids of 8 nm3 volume. The voids are defined by six phthalocyanines in a cubic arrangement with the metal ion of the macrocycle embedded at the centre of each face of the cube. The crystal structure allows unhindered access of small molecules (i.e. solvent and ligands) throughout the crystal so that it acts as a nanoporous material and it is possible to exert fine control over the coordination chemistry at the metal cations. The proposed programme of research involves realising the potential of this system in heterogeneous catalysis to perform biomimetic reactions of environmental relevance; in particular oxidation, dechlorination reactions and CO2 hydration. The possibility of using axial ligands to mimic the 'proximal' ligands found at the active site of enzymes may allow the reactivity and selectivity of the system to be enhanced. To test the potential of the various cubic structures, standard oxidation and dechlorination reactions will be carried out with systematic variations of metal cation, included solvent and proximal ligand. We will also assess the carbonic anhydrase-like activity of the zinc-containing crystals for the hydration of CO2 which is of relevance to sequestration technology.