Design, Synthesis And Properties Study Of N-Containing Heterocyclic Ligands And Their Cuprous And Iridium Complexes

As an important branch of heterocyclic compounds, N-heterocyclic compounds are very important organic intermediates and chemicals in the preparation of medicines, dyes, functional materials and so on. As a kind of organic ligands, they are widely used in the construction of metal complexes. In this thesis, we designed and synthesized a series of N-containing heterocyclic ligands and their cuprous and iridium complexes, and investigated their applications in luminescent materials, catalysis and medicines. The main work is concluded as below:In chart1, a general overview of the applications of N-heterocycle compounds and their metal complexes in luminescent materials, catalysis and biomedical areas is given. In light of this introduction, the design of thesis is outlined.In chart2, mononuclear Cu(I) complexes based on bis(pyrazol-1-ylmethyl)-pyridine derivatives and ancillary triphenylphosphine have been prepared and characterized by NMR, mass spectroscopy and single-crystal X-ray analysis. The electronic absorption spectra display two features in the regions of230-260and290-350nm attributable to mixed intra-ligand (LLCT) and metal to ligand charge transfer (MLCT) excited states, which is supported by the results of density functional theory (DFT) calculations on these Cu(I)complexes. These complexes are strongly emissive in the solid state at ambient temperature. Intense blue or green emission in PMMA film is observed in the region of475-518nm for these complexes with the emission lifetimes in the microsecond time scale, indicating that the emission should be phosphorescence. Increasing the steric hindrance of the substituents on the pyrazoleunit results in a blue-shift of the emission bands and enhanced emission quantum efficiency. The two most emissive complexes have been used for the fabrication of phosphorescent organic light-emitting diodes (POLEDs).In chart3, neutral mononuclear Cu(I) heteroleptic complexes based on2,2’-dipyridylamine (dpa), formulated as [Cu(dpa)(PPh3)X](X=C1(A4); Br(A5); I (A6)), and their counter parts with counterion, formulated as{[Cu(dpa)(P,P)](BF4)}(A1-A3) have been synthesized and characterized by NMR spectroscopy and single-crystal X-ray analyses. X-Ray analysis revealed that the central Cu(I) ion in all complexes is in a distorted tetrahedral coordination environment. The photophysical properties of these complexes in both methylene chloride solution and poly(methyl methacrylate) film have been studied. All the complexes display the typical metal to ligand charge transfer (MLCT) absorption band in the regions350-400nm. The complexes show broad and featureless luminescence at room temperature, with emission maxima that vary from494to562nm in the PMMA film depending on the electronic characteristics of the corresponding auxiliary ligand.In chart4, under mild conditions, the reactions of CuX (X=C1, Br and I) with18-crown-6(18C6) or benzo-18-crown-6(B18C6) in the presence of the corresponding potassium salts KX yield series of the CuX/crown-ether coordinated polymers (C1-C4) or dimmers (C5). Single crystal X-ray analyses show both C2and C3were constructed in a one-dimensional zigzag coordination polymer{[K(18C6)][CuX2]}n, with the CuBr2or CuCl2cluster units alternately connected by the cationic [K(18C6)]+bridges, and C4showed a ID polymeric structure of {[KI(B18C6)]2[Cu2l2]}n with Cu2I2rhombus alternately connected by sandwich-like [KI(18C6)]2. In contrast, a dimeric Cu(I) complexes{[K(B18C6)][CuBr2]}2(C5) was confirmed. At room temperature, the solids of C1, C2and C3exhibit very strong blue emissions, with the maximum peaks at502,476and495nm(λex=256nm), respectively, whereas C4displays a strong white luminescence at room temperature which can be attributed to halide-to-metal charge transfer(XMCT) and Cu2I2cluster-centered (CC) excited state. By lowering the temperature to77K, the C4changed to red luminescence, which is reversible when it back to room temperature.In chart5, a mesoporous silica (SBA-15)-supported iridium bipyridine complex is prepared by grafting of bipyridine onto the silica support, followed by complexation of an iridium(I) precursor in the presence of HBpin and cyclooctene. Structural analyses by X-ray powder diffraction, nitrogen physisorption, FT-IR, and solid-state NMR spectroscopy demonstrate that the3-dimensional, hexagonal pore structure of SBA-15is maintained after the immobilization. In particular, as a heterogeneous catalyst, this silica-supported iridium complex shows moderate to good catalytic activity in the aromatic C-H borylation of a variety of substrates. More importantly, the heterogeneous catalyst is recovered easily and reused repeatedly by simple washing without chemical treatment and exhibits good recycling performance with a modest decrease in the catalytic rate, showing good potential for increasing the overall turnover number of this synthetically useful catalyst.In chart6, three novel water-soluble porphyrin-indomethacin conjugates P2-P4were prepared and characterized. The binding properties of the cationic porphyrins to calf thymus DNA and HSA were studied by the means of various methods, such as UV-vis, fluorescence and CD spectroscopy. The cytotoxicity of P1, conjugates P2-P4and indomethacin against human cancer cells were investigated through MTT assay. Besides, through a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, we further verify the apoptotic cell death is induced by the PDT of porphyrin-indomethacin conjugates.