The Synthesis,Characterization And Study On The Properties Of The Ligand Containing N,O Atoms And Its Complexes

Being the fronts of current science and technology, both material science and life science have been extensively focused and thus the most active fields since 1970. Transition metal complexes hold the very important standing in both fields. For example, many metalloproteases act as the crucial roles in metabolism, in which their active sites are substantially composed of metal complexes. Various metal complexes also exhibit unique optical, electric, and magnetic properties, which are attractive for both design and development of new molecule-based materials. Both 8-hydroquinoline (HQ) and Schiff-bases possess the two ligating atoms (N and O), which could be further used to obtain a great deal of metal complexes with various structures and wide applications. In this thesis, we firstly developed a simple synthesis of aluminum 8-hydroquinolinate (Alq₃) using ultrasound method followed by the convenient analytic method. 5-Substituted HQ was thus designed and synthesized. The two corresponding Al³⁺ and Zn²⁺ complexes were obtained. Subsequent detailed studies indicated that both of them could be utilized as luminescent materials. Finally, new Schiff bases and their multiple nuclear Cu(II) complexes were developed and their corresponding biological activities were reported.Alq₃ is the most focused materials in organic electro-luminescent devices (OLED) up to now, which has been widely applied in various OLED. Being a luminescent compound, it should be kept with high purity. However, it is still difficult to obtain Alq3 with high purity in both industrial processes and laboratory, which means that further purification by chromatography or sublimation is necessary to improve the purity. We developed a new synthetic method to produce Alq₃ with high purities (99.91 - 99.99 %) and high yields up to 98 % based on ultrasound. In ultrasound, the coordination reaction was carried out in organic solvents at the absence of water and oxygen without the needs of introduction of bases, which could effectively avoid the formation of the dimmer and the fluorescence-quenching sites and thus provide good yields with high purities. The reported method could be performed at room temperature and atmosphere pressure accompanied with mild reaction conditions, shorter time. It should be regarded as a new economic and green method to Alq3. In addition, a new analytic method was developed based on inverse high-performance liquid chromatography.OPV unit with three alkoxy side chains was then introduced at the 5-position ofHQ. The design rationale was based on the fact that introduction of a substitute canalter the charge distribution along the molecular skeleton, modulate the luminescenceand improve the physical properties, which is supported by the theoretical calculationbased on DFT. Absorption and emission spectra of its corresponding Al³⁺ complexwas also calculated after analysis the frontier orbitals and optimization of thegeometric configuration at the ground state. This HQ ligand and its Al³⁺ and Zn²⁺complexes were thus synthesized and characterized by their elementary analysis,nuclear magnetic resonance, infrared resonance and MALDI-TOF mass spectra. Theiroptical and electric properties were subsequently studied. Both Al³⁺ and Zn²⁺complexes showed strong fluorescence at 563 and 558 nm, respectively. Compared tothe emission of Al³⁺ complex in solution, its fluorescence in solid state is red-shiftedto 582 nm. Electrochemical cyclovoltmetric studies indicated that substitution at HQincreased the HOMO level compared to the parent compound. The band width of thecorresponding Al³⁺ complex was thus decreased about 0.40 eV compared to Alq₃,which is in good agreement with the theoretically predicated results. Both complexesexhibited excellent thermal stability derived from their high decompositiontemperature (> 315℃) with good solubility in general solvents, such asdichloromethane and tetrahydrofuran. The two complexes are thus suggested ascandidates of luminescent materials.Finally, two tetranuclear Cu²⁺ complexes were constructed from a new salen ligand with alkoxo groups. The two complexes were obtained by the reaction of the same ligand with Cu²⁺ in different solvents, i.e., a stage tetranuclear complex and a pseudo-cubane tetranuclear complex in MeOH and THF, respectively. Both were measured using X-ray single crystal diffraction. For the crystal in MeOH, X-ray in compound. In an ansymmetry unit, there are two Cu(II) atoms, two ligands and twosolvent methanol molecules. The tetranuclear complex contains two kinds of Cu(II)center. Two Cu1 atoms each coordinate to the NO2 (a phenolic oxygen atom, analcoholic oxygen atom and an imine N atom) chelator unit in one ligand and analcohol oxygen atom from the other ligand, forming a distorted planar coordinationsphere. While two Cu2 each coordinate in a pyramidal geometry. Its distorted basalplane is also formed by the N2O unit and the alcohol oxygen atom from the secondligand, and an alcohol oxygen atom from the third ligand occupies the axial positionwith the Cu-O distance as 2.34 A. Two of the four alcohol oxygen atoms O3 in theligands act as oneμ2 bridged atom and the other two O6 act asμ3 bridge to link to Cuatoms together, resulting in the tetranuclear structure. Such structure can be describedas two Cu-Cu cores (separated in 3.05 A) linked by twoμ3 bridged alcohol oxygen06 and 06A atoms to form a centrosymmetric dimer of dicopper(II) moieties. For thecrystal in MeOH, X-ray single-crystal analysis reveals that each Schiff base provideone iminic N, one phenolic O and one hydroxylic O to chelate the four Cu(II) andthus resulted in a pseudo-cubane structure. Different from the crystal obtained inMeOH, each Cu(II) are tetra-coordinated not penta-coordinated. Such resultsindicated that the designed salen compound could be acted as bridged ligand withmultiple coordinative abilities and various aggregated possibilities in molecularstacking. The biological activities of the pseudo-cubane complex was furtherinvestigated, which shown a potent inhibition against Salmonela typhinurium, Proteusvulgaris, Pseudomonas aeruginosa, and Eschelichia coli.