Investigation Of The Effect Of Reaction Factors On The Formation Of Porous Coordination Polymers Based On4,4’,4"-benzene-1,3,5-triyl-tribenzoic Acid

Porous coordination polymers have recently attracted great attention due to their potential properties such as gas adsorption, ion-exchange, catalysis, magnetism, and optoelectronics and intriguing topologies such as molecular grids, bricks, herringbones, ladders, boxes, diamondoids, and honeycombs. In particular, the utilization of highly symmetrical multitopic ligands and suitable metal salts to construct metal-organic frameworks (MOFs) is of higher interest. However, the controllable synthesis of MOFs is of great challenge.In this dissertation, we focus on systematical investigation of the influence of some factors, such as solvent, temperature, acidity, and metal-ligand mole ratio on the formation of the coordination polymers based on highly symmetrical rigid tripodal ligand4,4’,4"-benzene-13,5-triyl-tribenzoic acid (H3BTB).This dissertation covers the following four parts:1. Chapter Ⅰ Introduction. Reviews on the research progress of MOFs were briefly made. The reticular synthesis of MOFs was depicted and the effects of synthetic conditions on the formation of coordination polymers were summarized in emphasis.2. Chapter Ⅱ. The main group metal salt Mg(NO3)2·6H2O was selected to react with H3BTB and five coordination polymers were obtained. Solvent effects on the assembly of Mg2+and BTB3-ions have been studied. When DMF was used as major component of solvent,3D1was formed which possesses mononuclear Mg(II) unit. But when major component of solvent was changed to DMSO, another compound,2, occurs which has a novel hexanulcear Mg6O3cluster. Interestingly, it is similar to1in structure and they have same space group. In the solvent of DMA, mixed with minor water,2D3was obtained which has a linear Mg3unit. But in the presence of CH3COO-ion, it bridges Mg2+ions instead of DMA molecule, resulting in3D4which contains infinite Mg-OCO chains. Solvent was altered into DEF,3D5with high porosity was acquired which has dinuclear and linear trinuclear moieties.From the synthesis conditions of complex1,2, and3and their structures, solvent DMSO and adequate water are crucial for forming Mg6O3hexanuclear cluster and the terminal coordination of DMA molecules to the linear Mg3cluster and the spacial hindrances of the molecules are key factors for forming2D layers in3. DEF molecule is a relatively big one and it is probably a template reagent for constructing5with non-interpenetration structure.3. Chapter Ⅲ. The metal salt In(NO3)3·4.5H2O was selected to react with H3BTB and five porous coordination polymers were obtained. The influences of solvent acidity and metal-ligand mole ratio on the formation of the structures of products have been observed. With the increase in the amount of HNO3used, three kinds of crystal,6,7, and8were gained, respectively, on the condition that DMA was selected as solvent and metal-ligand mole ratio was set to1:2. The results indicate that dimethylamine from the hydrolyzation of DMA was neutralized in different degrees with different amounts of HNO3added, which maybe influences the deproton of the ligand and further the configurations of the building blocks in the structures of products. When the ratio was adjusted to3:4, the fourth kind of crystal,9, occurred with the adapted amount of HNO3being added. Notably, these four complexes are polymorphs which frameworks are all constructed by mononuclear In(Ⅲ) units and BTB moieties. But under the condition similar to the synthesis of2, the fifth kind of In(Ⅲ) complex,10, was obtained which contains one type of trinuclear and two types of tetranuclear In-O clusters. 4. Chapter Ⅳ. The transition metal salt, Co(N03)2·6H20, was selected to react with ligand H3BTB and three kinds of coordination polymers were obtained. In the reaction, the synergistic effect of solvent and temperature on the formation of Co-O clusters has been systematically investigated. The results indicate that moderate temperature (105℃) and higher amount of DMF used facilitate the formation of Co3O cluster in11, higher temperature (125℃) and DMSO solvent are the key to forming Co4O cluster in12, and lower temperature (95℃) and higher amount of water used are in favor of the formation of Co6O3cluster in13in the presence of DMF with moderate amount. Additionally, the adsoption properties of12and13with similar structure were studied preliminarily.In summary,4,4’,4"-benzene-1,3,5-triyl-tribenzoic acid was selected as ligand in this work. The effects of the reaction factors, such as solvent, acidity and temperature, on the formation of porous coordination polymers have been investigated. It helps to enrich synthetic chemistry and structure chemistry and accumulate some valuable ideas for the design and synthesis of functional coordination polymers by the theory of crystal engineering.