Synthesis And Properties Of D¹⁰ Metal Complexes With Mixed1,3-Di（1H-imidazol-4-yl）Benzene And Multicarboxylate Ligands

With their variable structures and thermal/chemical stability, metal-organic frameworks (MOFs) show potential application in gas storage, catalysis, optic material, magnetism and soImidazole-containing ligands are good N-donor organic ligands due to their stable structures and variable coordination modes. In our previous studies, we have synthesized a series of imidazole-containing ligands, for example1,4-di(1-imidazolyl)benzene (bib),1,3,5-tris(1-imidazolyl)benzene (tib),1,3,5-tris(imidazole-1-ylmethyl)benzene (timb),1,3,5-tris(imidazole-1-ylmethyl)-2,4,6-trimethylbenzene (titb),1,4-di(1H-imidazol-4-yl) benzene (H2L1),1,3,5-tri(1H-imidazol-4-yl)benzene (H3L2). And a large number of metal complexes possessing intriguing structures and properties were obtained. Based on previous studies, we designed a new4-imidazole-congtaining ligand1,3-di(1H-imidazol-4-yl)benzene (H2L). This ligand has not only the features of imidazole-containing ligands but also more rich coordination modes in the case of the1H-imidazol-4-yl groups deprotonated.The multicarboxylate compounds are excellent O-donors organic ligands because of their versatile coordination modes and thermodynamic stability. Combination of imidazole-containing ligands with multicarboxylic acids has been demonstrated to be a useful strategy for construction of novel MOFs. On the other hand, d10metal complexes have properties in photoluminescence. For these reasons, we focus our attention in this study on reactions of ligand H2L together with different carboxylate ligands and d10metal salts, and make systematic investigation on the impact of carboxylate ligands, pH value and reaction temperature on the structure of the complexes.The1H-imidazol-4-yl-containing ligand used in this thesis is:Main research results of this work:1. Eight metal complexes [Zn(H2L)(m-BDC)](1),[Zn(H3L)(BTC)](2),[Zn(H2L)(HBTC)](3),[Zn(H2L)(HBTC)]·H2O (4),[Zn2(H2L)(BTC)(μ2-OH)](5),[Zn(H2L)(cis-1,2-CHDA)](6),[Zn(H2L)(trans-1,3-CHDA)]·2.5H2O (7),[Zn(H2L)(cis-1,3-CHDA)]·H2O (8), were obtained by reactions of zinc salts with H2L ligand and the corresponding carboxylic acids.1is1D chain,3is3D framework and all the others show2D layer structures. Hydrogen bonds play important role in formation of supramolecular structures. In2, H2L is protonated as H3L+to act as terminal ligand, and in other complexes, H2L ligands act as bridging ligands.2-4and7-8are two groups of complexes controlled by reaction temperature. We calculated the energy of these complexes by density functional theory (DFT) and the results indicated that thermodynamic factor is primary indictator the formation of the complexes.2and5are a group controlled by pH value. All the complexes have been investigated about photoluminescence.2. Seven metal complexes [Cd(H2L)(m-BDC](9),[Cd3(H2L)2(BTC)2(H2O)]·5H2O (10),[Cd(H2L)(cis-1,2-CHDA)]-3H2O (11),[Cd2(H2L)2(cis-1,2-CHDA)2]·3H2O (12),[Cd(H2L)(cis-1,3-CHDA)]·H2O (13),[Cd(H2L)(cis-1,4-CHDA)]·5H2O (14),[Cd(H2L)(cis-1,4-CHDA)](15), were obtained by reactions of cadmium salts with H2L ligand and the corresponding carboxylic acid.11,14and15are1D chains,9,12and13are2D layers,10is3D framework. All the1D and2D structures form3D framewoks through the connection of hydrogen bonds.11-12and14-15are two groups of complexes controlled by reaction temperature. The results of DFT calculation coincided with the experiment results. Photoluminescenc were observed in all the complexes.