| Currently, investigation about the novel coordination polymers with some special functions and structures has become an important scientific problem and hot spot, and the study to this field may afford more opportunities and possibilities to prepare and exploit new materials. Many reported results indicate that there are many factors to influence and direct the structures and functions of complexes. Among them, a key factor to prepare the desired materials is how to choose and design the suitable molecular building block. So, in this dissertation, combining the latest progress and actual situation of our group, we choose three isomeric flexible phenylenediacetic acids (H2pda) to isolate twenty-two new unreported compounds under hydrothermal condition. Then we tested and characterized the properties of the complexes, such as element analysis (EA), infrared spectra (IR), X-ray single diffraction analysis, thermo-gravimetric analysis-differential scanning calorimetry (TG-DSC), luminescence, powder X-ray diffraction analysis (PXRD) and magnetic susceptibility measurements;in addition, we also discussed the different roles of secondary ligands, metal ions, the steric effort of the dicarboxylate, reaction temperature and pH value to the properties-structures of the complexes, and summarized some helpful disciplinary conclusions. The major contents of this dissertation include five parts as follows:(1) To investigate the relationship of the structure and properties of coordination polymers, three various bridging pyridyl ligands were introduced in the same reaction system; and then three complexes 1-3 were successfully isolated. The results show that the minor modification of pyridyl ligand can result great differences about the structures and properties of complexes. In addition, the different water clusters existed in 1 and 2 can help to glue and expand the low dimensional networks. At the same time, the thermal stabilities and luminescence of 1-3 were also tested and analyzed.(2) Some factors, such as rigidity/flexibility of secondary ligand, steric bulk and metal ions et al., were studied to the structure-properties of complexes, eight different complexes were prepared. The roles of the aforementioned factors were discussed in the process of the formation of complexes. Also, the thermal stabilities of 5,8,9 and 11, the fluorescent properties of 9-11, the magnetism of 5 and 7 were carried out and discussed, respectively. (3) Two complexes have been isolated based on the meta-phenylenediacetic acid. Single X-ray structural analysis shows that complex 12 is a fully new five-folded interpenetrated network contained [3+2] catenation based on Ag…O interactions, and 13 is a three dimensional fsc framework with different chiral helical chains. The analysis of properties indicates that complex 12 has good luminescent materials, and complex 13 is an antiferromagnetic compound.(4) The steric effect of dicarboxylate ligand was investigated about the influence of the structures and properties of complexes based on three isomeric H2pda ligand, four Pb(II) compounds were successfully prepared. Among them, complexes 14 and 15 are true polymorphs which were isolated under the same experimental system at the different reaction temperature. Also, the thermal stabilities and fluorescent properties were compared and discussed carefully.(5) Both multi-pyridyl ligand and the steric effect of dicarboxylate ligand were studied to the formation of coordination polymers, five complexes were isolated in this part. Complex 18 is a two-folded interpenetrated pcu topological network based on O-H…H-bonded interactions, and 21 is a three-folded interpenetrated dia network with (2.2.1) Hopf links and (6.3.3) Torus links. In the same metal ions and secondary ligands, the further distance that the dicarboxylate groups of pda have, the more complicated coordination modes that the pda ligands adopt; the length and flexibility of the secondary ligand also have an influence on the resultant complexes. And the luminescent properties of five complexes were also measured.In a word, the research work of this dissertation not only enriches and broadens the contents of coordination chemistry and materials chemistry, but also afford a new idea and method to design and prepare functional coordination polymers. Therefore, this research work has some certain scientific means and application values.
|
PDF Full Text Request