Acid-bridged copper - rare earth heteropolynuclear Synthesis and research

Title: Acid-bridged copper - rare earth heteropolynuclear Synthesis and researchAuthor: Hou TingtingDegree-granting unit: Zhejiang University of TechnologyKeywords: rare earth;; transition metal;; shuttle acid;; heteropolynuclear;; crystal structure;; magneticSummary:As heteropolynuclear metal complexes of metal ions can exhibit many new physical and chemical properties, people in the late 1960s, the hybrid multi-core complexes interest. Of bridged 3d-4f mixed metal complexes of multi-core significance, store it in the gas, mixed gas separation, catalysts, light-emitting agents have potential application areas. Molecular Magnetic lifter materials can be seen by a large number of secondary structural elements are assembled according to a certain order with certain features of the system. By selecting the appropriate component units of molecules can be synthesized with a certain electrical, magnetic, optical properties of the particular structure of the polymer. Meanwhile, the design direction of the molecules are arranged in accordance with certain specific spatial structure of the synthetic method is also an important research direction.We have synthesized a number of carboxylic acid-bridged copper - rare earth complex polynuclear complexes and their structural and magnetic characterization. The following conclusions:(1) complexes of ① [CuGdL5Py (H2O)] n and complex ③ [CeCu2L'4LPy2 (NO3) 2 (H2O)] n structures are similar, space are all one-dimensional chain structure. X-ray analysis showed that the complexes ① is triclinic P (?) Complexes ③ space group and crystal system monoclinic space group P21. In the complexes [CuGdL5Py (H2O)] n in, Cu2 is four-coordinated, respectively, and a nitrogen atom from pyridine and methyl methacrylate from three of three oxygen atoms are coordinated to form an approximate square. Gd3 is eight-coordinate, respectively, and ligand methyl methacrylate in the seven oxygen atoms and one oxygen atom from the water ligand form a distorted square antiprism geometry. A Cu2 and a Gd3 ion and ligand through the formation of inversion operation - a quad-core structural elements (Cu Gd Gd Cu or Gd Cu Cu Gd), the structural units in the one-dimensional infinite space down to form a one-dimensional long chain. Complexes ③ [CeCu2L'4LPy2 (NO3) 2 (H2O)] n is a whole new structure, has not been reported. The complex formed by the heterotrinuclear structural unit, each structural unit contains two Cu (Ⅱ) ion, a Ce (Ⅲ) ions and four iso-radical ion, two nitrate ions, a methyl methacrylate ion, two pyridine molecules and one water molecule, the formula can be expressed as [CeCu2L'4LPy2 (NO3) 2 (H2O)] n. In these ligands in the carboxylate ion and methyl isobutyl acrylate ion as bridging ligand, two nitrate ions in chelating manner and Ce (Ⅲ) ions, two pyridine molecules are coordinated to a single tooth way and two Cu (Ⅱ) ions, and Cu in a water molecule is coordinated. Although the four iso-radical ion acts as bridging carboxylate ligands, but with a bit different form. Isobutyl radical ion using two bidentate bridging mode to connect Cu (Ⅱ) and Ce (Ⅲ) ions; the other two iso-radical ion addition to the bidentate bridging mode to connect Cu (Ⅱ) and Ce (Ⅲ) ion, but also to adopt the μ2-O-bridged form, that is an O on the carboxyl group at the same time with two Cu (Ⅱ) connection. Therefore, the iso-center ion-radical ion will link up to form one-dimensional chain structure. Complexes ② CuGdL5Py (HL) (H2O) in the structure significantly different from the complexes ① [CuGdL5Py (H2O)] n, the former is a discrete two core complex polynuclear complexes, Cu2 is five-coordinated pyridine, respectively, and from a nitrogen atom and three bridging methyl methacrylate from the root of three oxygen atoms and molecules in a neutral methacrylic acid with a bit of an oxygen atom to form an approximate square-pyramidal configuration. Gd3 is eight-coordinate, respectively, with two chelating methacrylate root of the four oxygen atoms and three bridging methyl methacrylate from the root of three oxygen atoms and one oxygen atom from the water ligand to form distorted square antiprism geometry.(2) complexes of ① and ② magnetic characterization showed that although both belong to {Cu-Gd} complex polynuclear complexes, due to different structures, magnetic properties have led to more obvious differences. Experiment 10000 Oe DC field (DC) (1 Oe = 4π × 10-3H), low temperature to room temperature were measured within the http://www.999magnet.com/products/131-magnetic-lifter magnetic susceptibility of the two complexes. Mapping of T to 1/xM curves obtained are well in line with Curie-Weiss law. Complexes at room temperature in the interaction between paramagnetic ions is almost negligible, so the two complexes, the Curie constant C are approximately equal. As the temperature decreases significantly different between the magnetic properties, we can see from the figure the value of Weiss constant 0 were-1.25K, O.137 K, indicating that complexes ① [CuGdL5Py (H2O)] n the performance of weak antiferromagnetic , while the complex ② CuGdL5Py (HL) (H2O) showed weak ferromagnetism, which is due to complexes between ① in the Cu ... Cu antiferromagnetic effect than Cu ... Gd caused between the magnetic effect, so demonstrate the apparent antiferromagnetic interaction; in molecular complexes ② there are only Cu ... Gd role between the ferromagnetic. However, at very low temperatures, the complexes between ① and ② in antiferromagnetic molecular role will become more apparent, are reflected in relatively strong antiferromagnetic interactions.Degree Year: 2010