dc.description.abstract | In this thesis, we focus on two areas: 1) synthesis, structural characterization of metal phosphates incorporating organic ligands; and 2) synthesis, structural characterization of coordination polymers containing polyoxometalates. In the first area, we plan to use 2,2’-bipyridine or 1,10-phenathroline to synthesize a new organic-inorganic hybrid compound. Most of these compounds contain neutral frameworks without organic amine templates. Metal phosphates containing organic components coordinated directly to metal atoms are scarce, as compared with the large number of metal phosphate in literature where the organic components mostly occur as charge compensating and space-filling constituents. We already have synthesized 7 compounds with novel structures, we excerpt some conclusions as following: (a) It appears that the addition of HF to the reaction mixture is important to the formation of A-1 and A-2, (b) It appears that the addition of LiBO2 to the reaction mixture is important to the formation of A-3H and HF facilitates the crystal growth, (c) Two polymorphs (A-5 and A-6) of an organic-inorganic hybrid compound have been synthesized by hydrothermal reactions. The synthesis has many parameters and a subtle change in the reaction conditions can greatly affect the course of the reactions. It appears that the addition of TEABr to the reaction mixture is important to the formation of A-5, and (d) all compounds consist of similar secondary building units which are extend into 3D supramolecular arrays via hydrogen bond and π-π stacking interactions of 2,2’-bpy or 1,10-phen ligands.
In the second area, we are interested in coordination polymers containing polyoxometalates. We already have synthesized 8 compounds with novel structures, we excerpt some conclusions as following: (a) although a good number of compounds containing anionic M[Mo6P4]2 dimers connected by transition metal complexes have been reported, B-1 is the first example of extended framework solid containing the polyoxomolybdophosphate clusters interconnected by both transition metal complexes and organic moieties, (b) B-4 represents the first example of molybdenum-oxide-based organic-inorganic hybrid frameworks templated by double Keggin anions. With hindsight, we can imagine that more new metal-oxide-based hybrid materials could be prepared by replacement of organic-manganese complex segments and/or by selection of different Keggin anion or other polyanion templates, (c) for B-5 and B-6, there is no doubt that the nature of the secondary transition metal ion, Cu(II), has a key role in the formation of these novel structures because of its capacity to adopt various coordination environments and the Jahn-Teller effect which allows an elongation of the axial Cu-O and Cu-Cl distances, (d) the 3D structure, B-7, based on a transition-metal coordination polymer sheet linked by Strandberg clusters, and (e) a new derivative of polyoxometalate, B-8, with a pendant organic ligand, which represents a rare organic capped-structure containing Keggin polyanion. | en_US |