Synthesis, Structure And Morphology Transfer Of Transition Metal-Carboxylate Coordination Polymers

The aim of this thesis is to synthesize new coordination polymer with one-dimensional chain structure on the basis of aromatic carboxylic acid ligands and transition metal ions, to study the influence of ligands structure and synthetic conditions to the formation of one-dimensional chain, and to explore the relationships between structure and property. Another aim of this thesis is to study the morphology transfer mechanism and rules of coordination compound precursors with one-dimensional chain transformed to inorganic nano-crystals, to find a new way for the controlling synthesis of one-dimensional nano-structural materials.This thesis investigated the synthesis, structure and property of coordination polymers with one-dimensional chain structure constructed from benzene-dicarboxylic acid, iso-nicotinic acid and transition metal ion; the procedure via solid-state transformation of coordination polymer with one-dimensional chain to synthesize oxide nanowires has been especially investigated and discussed.Three coordination polymers: [C₈H₆CdO₅]_n(1), [C₈H₁₀CdO₇]_n·4H₂O (2) and [C₈H₆ZnO₅]_n (3) on the basis of benzene-dicarboxylic acid were synthesized by sovol-thermal method and characterized by single crystal X-ray diffraction. Structural analysis revealed that compound (2) displayed one-dimensional chain structure and compound (2) and (3) were three-dimensional network structure. Solid-state fluorescent spectrum revealed that three compounds all displayed strong blue fluorescent. Four iso-structural supra-molecular compounds [C₁₂H₁₆MN₂O₈]_n(M = Co (4), Zn (5), Cd (6), Mn (7)) and two coordination polymers [C₂H₆CoO₆]_n(7), [C₁₂H₁₀CoN₂O₄]_n (8) on the basis of iso-nicotinic acid were synthesized by sovol-thermal method and characterized by single crystal X-ray diffraction. Structural analysis revealed that compound (4-7) were three-dimensional network constructed from hydrogen-bonding interaction between mononuclear structure, compound (8) and (9) were three-dimensional network structure. Solid-state fluorescent spectrum revealed that two compounds (5 and 6) formed by Zn²⁺ and Cd²⁺ displayed strong blue fluorescence.To control reaction condition, the transformation from coordination polymer to supra-long CdO nano-wires with average diameter was achieved by using synthesized cadmium coordination polymer with one-dimensional structure as precursors. The prepared nano-wires were characterized using XRD, TEM, EDX, HRTEM and its optical properties were examined, and the growth mechanism of nano-wires was discussed. The results indicated that the one-dimensional chain geometry of molecular scale was inherited during the solid-state transformation course. The successful preparation of CdO nano-wires from coordination polymer with one-dimensional chain structure made it possible of morphology transfer from molecular scale to nano-scale and provided a new way for the controlling synthesis of nano-materials in molecular dimensionality.