Research On Arylpolycarboxylate Coordination Polymers: Synthesis, Structure And Function

According to a survey of lots of literatures, this thesis reviews the structural characterization and main growth mode of coordination polymers, and goes into particulars on the special performance of some coordination polymers based on their unusual structures. This thesis also presents the relationship between the characterization structure and functions of coordination polymers elementally, and their development in functional materials of non-linear optics, luminescence, gaseous absorption, heterogeneous catalysis and ion exchange. In view of the main research direction of this thesis, the polycarboxylate coordination polymers are especially discussed, and the certain relationship between their given functions and their microcosmic crystal structures are illustrated.The strategy of the research is "to choose organic ligands→to construct the corresponding coordination polymers→to decorate the organic ligands (according to the need of specific architecture and functions)→to synthesize a new compound...". A series of organic ligands with special structures are synthesized, following with the diverse mental-organic frameworks are constructed under hydrothermal conditions. The detailed research work was as follow:1. Eight kinds of polycarboxylate ligands were prepared according to the need of research on the luminescence and gaseous absorption properties of coordination polymers. The reaction of them with various mental salts under different conditions, such as solvents, temperature and crystal growth time, gives rise to eight diverse mental-organic frameworks.2. Two new isostructural coordination polymer [Cd(Hadab)(H₂O)] (1) and [Mn(Hadab)(H₂O)] (2) (H₃adab = 3-aminodiacetic benzoic acid) have been synthesized under hydrothermal conditions and characterized by X-ray single crystal analyses. Compounds 1 and 2 represent 2D network, whose 3D pillar-layered networks are constructed by hydrogen bonding interactions. Compound 1 may be excellent candidates of blue light-emitting materials, by right of intense room temperature photoluminescence in the solid state, highly thermally stable and insoluble in common polar and nonpolar solvents; compound 2 displays strong fluorescent emissions too, the correlative reports are very rare due to specific electrons transfer capability of Mn.3. Four new organic ligands are prepared based on the limitation of the coordination of compounds 1 and 2( the carboxyl connected directly with the aromatic cycle does not take part in the coordination), such as organic ligand two: 3-(carboxylmethyl amino)benzoic acid, organic ligand three: N, N'-di-(4-carboxylphenyl) -4-aminobenzoic acid, organic ligand four: N, N'-di-(4-carboxylphenyl)-2-aminobenzoic acid and organic ligand Five: N, W-di-(2-carboxylphenyl)-2-aminobenzoic acid. However, the expected single crystal does not obtained. But when organic ligand three and organic ligand four react with Cd(ClO₄)₂·6H₂O in alkaline solvent system, crystals easy to collapse are obtained, which may due to a large pore space framework.4. A novel imidazo[1,2-a]pyridin-2-one ligand, 3,3-bis(carboxymethyl) imidazo[1,2-a] pyridin-2-one (H₂L), was inexpectantely synthesized and acts as a three-connecting T-shaped building block, affirmed by X-ray single crystal analyses. Hydrothermal treatment of the H₂L ligand with Cd(ClO₄)₂·6H₂O or Zn(ClO₄)₂·6H₂O gives three new coordination polymers, [CdL(H₂O)₂]n (5) , [ZnL(H₂O)]n (7)and [CdL(H₂O)] n(8). Compound 5 consists of a rare 1D ladder-like chain, which is composed of two kinds of alternating rhombic rings with step lengths of 4.78 and 5.16 A, respectively. Though it is absolutely identical that the material to construct compound 5 and compound 8, the latter represents a much more rare 2D network with the 4*8² topology, it owe to solvent effect that comes from different solvent . Compound 5, 7 and 8 are also exhibits strong photoluminescence, they may be excellent candidates for potential photoactive materials.5. A new mental-organic coordination polymer 9 is hydrothermally synthesized through the reaction of the in situ dimer of organic ligand seven (imidazo[1,2-α]pyridin-2-one) with Zn ion. According to the analysis the structure and function of the coordination polymer 9, we find that it is also a potential fluorescent material. Besides, it may have unpaired electron in its configuration, and further research is in progress.6. In order to obtain steady large pore space framework. we synthesized organic ligand eight. Disappointedly, only yellow solid can be obtained through improved interphase diffuse method. Hydrothermal conditions are unfeasible on account of too many unsaturated bonds in the organic ligand. The growth conditions of single crystal is under exploration.