Harvey, Howard Glen;
(2003)
The chemistry of new group 13 metal diphosphonate materials.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
This thesis describes the synthesis, characterisation and properties of new aluminium and gallium diphosphonate materials. All the materials were prepared using an HF/ pyridine solvent system and their structures were resolved using single crystal and ab initio powder X-ray diffraction methods in addition to standard laboratory techniques. Five framework materials were synthesised [Al2(O3PC2H4PO3)(H2O)2F2]-H2O, [alpha]-[Ga2(O3PC2H4PO3)(H2O)2F2]H2O, [beta]-[Ga2(O3PC2H4PO3)(H2O)2F2]-2H2O, [Al2(O3PC3H6PO3)(H2O)2F2].H2O and Ga2[O3PCH2(C6H4)CH2PO3](H2O)2F2. These consist of Al/P/O/F inorganic layers linked by organic diphosphonate moieties to form three dimensional frameworks with various degrees of porosity. Numerous aspects of these materials have been investigated including a full structural analysis of the dehydrated material [Al2(O3PC2H4PO3)(H2O)2F2].0.51(3)H2O, the substitution of smaller phosphite moieties for diphosphonate as a method to increase the resultant porous volumes and the thermal and readsorptive properties of the materials. Computational techniques, applying density functional theory, were used to probe the energetics of the aluminium diphosphonates and allows a rationalisation of the different structures formed. The use of organic amines to form new structures is investigated, using linear amines as solvents or as added structure directing agents, Propyldiamine results in the chain structure (H3NC3H6NH3)2[Al2(H2O)2F6(O3PCH2CH2PO3)]. Propylamine, ethyldiamine, and ammonium result in (C3H7NH3)[AlF(HO3PC2H4PO3)], (H3NC2H4NH3)[Al(OH)(O3PC2H4PO3)] and (NH4)2[AlF(O3PCH2PO3)] respectively. These materials form chains, related to the mineral tancoite, in which the arrangement of the chain is dependent upon the amine size and shape. The use of the methylene diphosphonate ligand results in (C5H5NH)[Ga2(H2O)2(O3PCH2PO3)(O3PCH2PO3H)], (C5H5NH)[Ga(H2O)(O3PCH2PO3)], [N(CH3)4][Ga2(H2O)2(O3PCH2PO3)(O3PCH2PO3H)] and (C5H5NH)- [AlF(HO3PCH2PO3)](H2O)0.58(1. The first three materials posses the same layer structures with different interlayer contents. (C5H5NH)[Ga2(H2O)2(O3PCH2PO3)(O3PCH2PO3H)] and [N(CH3)4]-[Ga2(H2O)2(O3PCH2PO3)(O3PCH2PO3H)] form a hydrogen bonded network whilst (C5H5NH)[Ga(H2O)(O3PCH2PO3)] has a layer structure in which the pyridinium cations can be partially exchanged for various metal salts to form a material related to (C5H5NH)[Ga2(H2O)2(O3PCH2PO3)(O3PCH2PO3H)]. (C5H5NH)[AlF(HO3PCH2PO3)](H2O)0.58(1) consists of a chain structure which hydrogen bonds to form an open framework three dimensional structure.
Type: | Thesis (Doctoral) |
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Qualification: | Ph.D |
Title: | The chemistry of new group 13 metal diphosphonate materials |
Open access status: | An open access version is available from UCL Discovery |
Language: | English |
Additional information: | Thesis digitised by ProQuest. |
Keywords: | Applied sciences; Diphosphonate materials |
URI: | https://discovery.ucl.ac.uk/id/eprint/10102014 |
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