Functions Of Metal Ion As Template And Catalytic Center: Synthesis, Crystal Structures And Property Of First Transition Metal Complexes Of Schiff Bases, Ketone Hydrazone And Aryl Polycarboxylic Acids

The thesis, using the first transition metal complexes of Schiff bases, ketone hydrazones and aromatic multicarboxylic acids as objects, investigates deeply the functions of metal ions in the course of complex formation. The results confirm that metal ions influence the assembly and configuration of coordination compounds through their coordination preference and size. During in situ formation of ligands, metal ion plays template and catalytic site. The main outcomes can be cited as follows.(1) We will report a new effect in template-directed Schiff bases formation, a series of linear structures in accordance with the precise coordination requirements of the metal ion. The nature of metal template determines the outcomes of Schiff base condensation between a carbonyl component (2-acetylpyridine) and some terminal-diamines. Six Ni(II) complexes, [Ni(L^I)₂](ClO₄)₂ (1), [Ni(L^II)](ClO₄)₂ (2), [Ni(L^III)](ClO₄)2.H₂O (3), [Ni(L^IV)](ClO₄)₂ (4), [Ni(L^v)₃](ClO₄)₂ (5) and [Ni₂(L^VI)₂Cl₃](ClO₄) (6) were formed, but single-crystal X-ray diffraction reveals that the chemical structure of the main product is metal-ion dependent. All the complexes have 6-coordinated Ni(II) center(s) and the ligands L^I - L^VI are differently condensed, of which L^VI is non-, L^I, L^III and L^V are mono- and L^II and L^IV are bi-condensed. The ligands L -L are prepared in-situ in the present of metal cations. The different content of metal salts reveals significant difference to the rigid bridged group NH₂NH₂, but no obviously functions to flexible chains, such as NH₂CH₂CH₂NH₂. Using the different metal ions, including Cu²⁺, Zn²⁺ in place of Ni²⁺ as metal-ion sources indicates same effect to the formation of the above ligands, which provides an inverse observation to pervious works.(2) X-ray crystal studies on a Ni(II) and a Cu(II) complexes, [Ni(L)₂](Cl)₂(H₂O) (1), [Cu(L)](Cl)(H₂O) (2) (L^I = diethylenetriamine) reveal a new type of full-hydrogen-bond chain [···Cl···H-O-H]_n^n-, existing in both 1 and 2 as paired M and P helices having 2-fold screw axes parallel to b, and thermal analysis of 1 shows that the water molecules in chain evaporate at 105°C accompanied by an enthalpy chang of 27.2kJ.mol^-1.(3) Galactose oxidase (GOase) is a fungal enzyme functionally capable of catalyzing aerobic...