Synthesis and characterisation of novel functional phthalocyanine nano-porous materials

Abstract

This project was focused on the synthesis of novel phthalocyanines for the construction of porous molecular crystals that incorporate the desirable properties associated with phthalocyanine complexes. Conventional phthalocyanines are relatively insoluble, therefore, remain difficult to process, characterise and effectively crystallise. To counteract this problem, bulky 2,6-di-iso-propylphenoxy substituents were placed around the aromatic core of the phthalocyanine macrocycle and proved to successfully inhibit the co-facial aggregation which limits their solubility. These bulky groups also direct the crystallisation of the phthalocyanine macrocycle inducing a cubic packing arrangement with significant accessible solvent filled voids. The aim of this work was the modification of this 2,6-di-isopropylphenoxy substituted phthalocyanine to enhance the magnetic and catalytic properties and demonstrate its suitability as a platform for creating iso-reticular systems with increased functionality. It was anticipated that mixed double decker complexes of this derivative and another phthalocyanine macrocycle would form crystals with the same cubic spatial arrangement, while maintaining their high catalytic activity or single molecular magnetism behaviour. Firstly, a larger number of transition metals along with some lanthanide metals have been incorporated within this substituted phthalocyanine, extending the previous work on this system. Furthermore, the corresponding contracted macrocycle boron subphthalocyanine was also investigated. While the 2,6-diisopropylphenyl substituents did not greatly affect the electronic properties of the subphthalocyanine, the solid state properties of the material proved interesting. The lanthanide phthalocyanine complexes were further employed in the preparation of lanthanide double decker phthalocyanines that possess single molecule magnetic properties. While retaining this desired property, they also crystallised to produce clathrates with large solvent filled voids. A different double decker complex which contained two iron metal centres bridged by a single nitrogen atom was also prepared from the octa substituted 2,6-di-iso-propylphenoxy phthalocyanine and an unsubstituted phthalocyanine. This nitrido bridged di-iron phthalocyanine complex displayed similar catalytic activity to previously reported systems of this kind and crystallised to afford cubic crystals with large solvent filled voids. These were shown to be accessible by both solvent and ligand exchange. Suitable bidentate ligands for structural stabilisation could be also incorporated. Finally, the preparation of an alternatively substituted phthalocyanine for the construction of a potential porous molecular crystal was studied. By synthesising a hexamethylindan substituted phthalonitrile, it was possible to obtain a soluble phthalocyanine that crystallised to give a clathrate that contained large one-dimensional voids.