Series Of Coordination Polymer Synthesis, Characterization, And Nature Study

Metal-organic coordination polymers are assembled from organic ligands together with one or more types of metal centers via coordination bonds. Design and properties of the supramolecular metal coordination complexes are involved in many fields including inorganic, organic, coordinate chemistry, material chemistry and life science et al. As a new type of porous materials which may possess high specific surface area, versatile structures and are easy to be functionalized, they have become a widespread focus in the field of material science with respect to their structure and potential applications in optics, magnetis, catalysis. In this paper, nine novel complexes have been hydrothermally and solvently obtained and characterized by single crystal X-ray diffraction, thermal analysis, elemental analysis,IR spectroscopy and fluorescence. The main achievements and creativity are given below:(1). Three novel europium (Ⅲ) complexes, [Eu2(INO)2(ox)2(H2O)2]n (1),{[Eu2(INO)2(suc)2]·2.99H2O}n(2) and{[Eu2(suc)3(H2O)2]·H2O}n (3) (HNNO=nicotinic acid N-oxide, H2ox=oxalic acid, HINO=isonicotinic acid, H2suc=succinic acid) have been synthesized under hydrothermal conditions and characterized by IR, elemental analysis, TG/DTA and single crystal X-ray diffraction analysis. The 3D frameworks 1,2,and 3 are different due to the different coordination modes of the carboxylates and ligand conformations assumed by succninate. The 3D open frameworks 2 and 3 have bigger channels filled with solvent water molecules than frameworks 1 do, showing that the presence of channels whose size is influenced by the length of the used acyclic binary carboxylates. At room temperature, the complexes 1,2 and 3 in solid state exhibit typical red luminescence from Eu3+ions, however, the luminescence intensity of them is obviously different due to the difference of their crystal and molecular structures. Compared with complex 2, both the complexes 1 and 3 exhibit weaker luminescence due to oscillation of coordinated water molecules, indicating that the energy transfer from the ligands to Eu3+ion in 2 is the most effective.(2). Three novel transition metal-organic frameworks based on a flexible ligand 1,3-bis (4-pyridyl)propane (bpp) with helical structures, [Zn(C7H7SO3)2(bpp)2]n (4), [Cu2(SCN)2(NO3)2(bpp)4]n (5), {[Cu5(SO4)5(bpp)8(H2O)5(C2H5OH)]·(H2O)31(C2H5OH)}n (6) have been synthesized successfully and characterized. Single crystal X-ray diffraction analysis reveals that both 4 and 5 exhibit 2-D layer networks composed of alternate right-handed and left-handed helical chains by sharing Zn(Ⅱ) or Cu(Ⅱ) ions, respectively. Interestingly,5 has two interpenetrating 2-D layer networks. While 6 has a 3-D interpenetrating structure constructed by 1-D helical double chains and 2-D parallel layers linked by sulfates which are further linked by SO42- anions. Compound 4 exhibits blue emission in solid state indicating efficient energy transfer of metal-to-ligand or ligand-to-metal, Electrocatalytic properties of compound 5 and 6 were investigated. It is observed that irreversible reduction peak in 6 is more lower than that in 5, less activation energy is needed in the one-electron reduction in 6.(3). Three new organic/inorganic hybrid complexes Na[AlMo6(OH)6O18](C7H8NO2S)2·2H2O (C7H7NO2S= 4-pyridylthio)acetic acid) (7), Na2(C6H5NO2)2(C2H3O2)2Eu2[AlMo6(OH)6O18]2·33H2O (C6H5NO2= nicotinic acid, C2H3O2= acetate) (8) and (C6H5NO2)2(C2H3O2)2Eu2[AlMo6(OH)6O18]2(H3O)2·28H2O (C6H5NO2= isonicotinic acid) (9) based on [AlMo6(OH)6O18]3- polyoxoanions as building blocks have been gained. Compound 7 possesses two-dimensional layer structure constructed from Anderson polyanions bridged by Na+ cations, while the protonated (4-pyridylthio)acetic acid molecules are situated between the layers via hydrogen bonds. Compound 8 displays a three-dimensional supramolecular framework built up of the Anderson type anions and Eu-nicotinic acid coordination complexes, in which two type of 1D chains are formed:the first type refers to that formed by Anderson polyoxoanions and Eu-nicotinic acid coordination complexes, and the second type refers to that formed by Anderson polyoxoanion and Na+ cations. The two types of chain are vertically cross-connected with each other. Compound 9 possesses a novel one-dimensional chain structure formed by the Anderson polyoxoanions and Eu-isonicotinic acid coordination complexes. The free polyanions are situated between the chains via hydrogen bonds.