Syntheses, Structures And Properties Of Coordination Polymers Based On Imidazole Dicarboxylic Acid And Schiff Base Both Containing Triazole Ring

The chemistry of functional coordination polymers constructed by 4,5-imidazole dicarboxylic acid and Schiff base has been of growing interesting due to their potential applications in the areas of absorption, catalisis, biological activity, luminescence,and so on. In the dissertation, we introduce triazole group into the backbone of 4,5-imidazole dicarboxylic acid and Schiff base, and synthesize two new ligands,2-((1H-1,2,4-triazol-1-yl)methyl)-1H-imidazole-4,5-dicarboxylic acid (H3TMIDC) and N'-(pyridin-2-ylmethylene)-2-(1H-1,2,4-triazol-1-yl)acetohydrazide (HPMTAD). We have obtained eight novel coordination polymers and especially investigated their structures. Their fluorescent properties have been studied. The results are outlined as follows.Six novel metal compounds, namely, Mn(H2TMIDC)2(H2O)2 (1), Fe(H2TMIDC)2(H2O)2 (2), [Fe0.5(H2TMIDC)2(H2O)2]n (3), [Cd(HTMIDC)]n (4), [Mn1.5(TMIDC)(H2O)5]n (5), [Cu3(TMIDC)2(H2O)]n (6) have been synthesized by 2-((1H-1,2,4-triazol-1-yl)methyl)-1H-imidazole-4,5-dicarboxylic acid (H3TMIDC) and transition metal salt. The structures of 1 and 2 are alike, and both of them are molecules. The 3D supramolecular structures of them are formed by the linkage of hydrogen bonds andπ-πinteractions. Compound 3 has been obtained from compound 2, in high temperature and high pressure conditions. The 1D chains of 3 are linked by hydrogen bonds forming 3D framework. In compound 4, the 3D structure is constructed byπ-πinteractions among triazole rings of adjacent layers. Excitation at 360 nm leads to emission band at 442 nm for the compound 4. And the emission can probably be assigned to the intraligand (π-π) fluorescent emission. The analysis of compound 5 reveals that it is a 3,4-connected net with (63.83) (63) topology, where the Mnl ions and TMIDC3- ligands act as 3-and 4-connected nodes, respectively. Each asymmetric unit of compound 6 contains three Cu ions, and the ions are linked by ligands forming 3D framework.Two compounds, namely, Cd2(HPMTAD)2(NO3)4(CH3OH)2 (7) and Cu2(PMTAD)2(C1O4)2 (8) have been synthesized by N'-(pyridin-2-ylmethylene)-2-(1H-1,2,4-triazol-1-yl)acetohydrazide (HPMTAD) and transition metal salt The structures of 7 and 8 are alike, both of them are molecules. In compound 7, the molecules are linked byπ-πinteractions constructing 1D chains, furthermore, by the linkage of hydrogen bonds, the 1D chains are connected together forming 3D framework In compound 8, the molecules are linked byπ-πinteractions constructing 1D chains. Furthmore, their fluorescent properties have been investigated in the DMF solution at room temperature.