Syntheses, Structures And Properties Of Zn(Ⅱ) Coordination Polymers Based On Isophthalate Derivatives

In recent years, coordination polymers based on organic ligands and metal ions have become an attractive and promising research field. Coordination polymers are not only possess intriguing structure topologies, but also show attractive characteristics, such as flexible tailorabilty, good modifiablity and ready functionalization. It has a potential application in fluorescence, electronic chemistry, magnetism, gas-storage and separation as well as catalysis. It is well known that the properties of coordination polymers are mainly defined by their structures. Therefore, it is important to investigate self-assembly process of organic ligands and metal ions as well as factors influencing the structures of coordination polymers. The most fascinating task in this field is to obtain complexes with novel structures and unique properties through selecting appropriate organic ligands and metal irons as well as controlling the influential facors in self-assembly process based on the principles of crystal engineering and self-assembly.This thesis is to choose 5-nitroisophthalic acid, hydroxyl-substituted 5-hydroxyisophthalic derivatives and flexible bi(imidazolyl) ligands as mixed ligands to construct coordination polymers. Our aim is to study the influence of different 5-positioned substituents of isophthalate on the structures and properties of the coordination polymers.In this thesis, we have selected the rigid carboxylic ligands,5-methoxyisophthalic acid (MeO-H2ip),5-ethoxyisophthalic acid (EtO-H2ip),5-propoxyisophthalic acid (PrO-H2ip),5-nitroisophthalic acid (NO2-H2ip), and flexible bi(imidazolyl) ligands 1,4-bis(imidazol-1’-yl)butane (bimb),1,4-bis(2-methylimidazol-1-yl)butane (bmib), 1,3-bis(2-methylimidazol-1’-yl)propane (bmip) to react with Zn(Ⅱ) ions under the hydrothermal and solvothermal conditions, and ten coordination polymers [Zn(EtO-ip)(bimb)]n(DMF)n(1), [Zn(PrO-ip)(bimb)0.5]n (2), [Zn2(NO2-ip)2(bimb)2]n(H2O)n (3), [Zn(NO2-ip)(bimb)]n(H2O)0.5n (4), Zn(MeO-ip)(bmib)0.5]n(H2O)0.5n (5), [Zn(EtO-ip)(bmib)0.5]n (6), [Zn(PrO-ip)(bmib)]n (7), [Zn(NO2-ip)(bmip)]n(H2O)1.5n (8), [Zn4[MeO-ip)3(bmip)(OH)2]n (9), and [Zn(PrO-ip)(bmip)] n(H2O)2n (10) were obtained. Single crystal X-ray diffraction analyses showed that complexes 1,5,6,7,8, and 10 are two-dimensional layer, while complexes 2, 3,4, and 9 are three-dimensional networks. Their elemental analysis, IR spectra, X-ray powder diffraction, thermogravimetric analysis, and luminescent properties were also investigated.