Syntheses, Structures And Luminescence Properties Of New Transition And /or Lanthanide Coordination Complexes Of Carboxylic Acid Derivatives Of 2,2':6',2"-Terpyridine

With the rapid development of science and technology, materials science-as one of the high-tech, especially functional materials is showing extremely strong momentum of development in recent decades. Functional materials, biological technology, energy technology and information technology have been the hottest research topic in 21 st century. The research of functional materials used for light-emitting display and optical communication has been the forefront field in materials and information science due to their great potential applications in national cutting-edge technology, aerospace field, computer technology, information, laser, etc. The dissertation is aimed to synthesize transition and/or lanthanide coordination complexes of carboxylic acid derivatives of 2,2':6',2"-terpyridine with excellent photophysical properties. Four series,25 transition and/or lanthanide coordination complexes are successfully designed and constructed by the reactions of transition metal (RuⅢ, RuⅡ, ZnⅡ, CdⅡ) and/or lanthanide ions (NdⅢ,PrⅢ,EuⅢ,TbⅢ,DyⅢ) with four kinds of carboxylic acid derivatives of 2,2':6',2"-terpyridine with different lengths and rigid flexible spacers. The coordination complexes are characterized by X-ray single crystal diffraction, IR spectra, elemental analyses, UV-visible spectral analyses. Their luminescence properties have been investigated by steady-state/transient luminescence technology. Their thermal stabilities have also been studied by thermal gravimetric analyses. The dissertation includes five chapters as follows:Chapter 1:The concepts and principles of coordination chemistry, coordination polymers and supramolecular chemistry are simply introduced. The research contents of photochemistry, the theory and the research fields of metal organic luminescent complexes were briefly depicted. Reviews on luminescence properties of 2,2':6',2"-terpyridine derivatives and research development of carboxylic acid derivatives of 2,2':6',2"-terpyridine were also briefly summarized.Chapter 2:Seven novel ZnⅡcoordination complexes with dinuclear (3), 1D (2,4-7),2D (1) structures based on 4'-carboxy-2,2':6',2"-terpyridine (HL1) and aliphatic dicarboxylic acid with different lengths as auxiliary ligands have been synthesized successfully; Three isostructural lanthanide (EuⅢ, TbⅢ, DyⅢ) complexes (8-10) based on HL1 with excellent luminescence in visible range have been synthesized successfully; Two 3d-4f heterometal complexes constructed from HL1, ZnⅡ, NdⅢ(11)/PrⅢ(12) have been synthesized. The influence factors of aliphatic dicarboxylic acid with different rigid flexiblility, reaction conditions have been discussed. The results is that during the construction of the structure, the anions of the metal salts, rigid flexiblility of the auxiliary ligands, pH values, molar ratio of the reagent, reaction temperature, et., can regulate and control the structure to some extent. The luminescence properties and thermal stability of the complexes have been investigated. The energy transfer efficiency in 8-12 has been discussed.11-12 show good NIR luminescence properties and long phosphorescence lifetime.Chapter 3:4'-(4-carboxyphenyl)-2,2':6',2"-terpyridine has been synthesized by modified method. A series of lanthanide coordination polymers (13, 1D) and two novel transition metal complexes (Cd", mononuclear; Zn", ID) based on HL2 with good luminescence preoperties have been synthesized successfully. Theπ-πstacking interactions and hydrogen weak interactions play an important role on the constructing of 3D supramolecular network. The influence factors of constructing and controlling structures, such as metal salts (metal ions, anions), auxiliary ligands, molar ratio of the reagent, pH values, et al, have been studied systematically.Chapter 4:4'-(4-carboxymethoxy-phenyl)-2,2':6',2"-terpyridine (HL3) which has never been reported has been synthesized by modified one pot reaction. Six novel transition metal (CdⅡ, ZnⅡ) coordination polymers based on HL3 and rigid flexible aliphatic or aromatic dicarboxylic acid have been synthesized successfully, with structure of 1D zigzag chain (16, 17), 1D ladder shaped chain (18,19) and 2D double fold interpenetrated network (20,21). In these complexes, metal ions affected the coordination modes of HL3. The multidimensional structures can be more easily obtained by zinc acetate than zinc chloride. All complexes show strong blue-green luminescence properties with lifetime on nanosecond level. They may be used as potential blue-green luminescence materials.Chapter 5:4'-[4-N,N-bis(carboxymethyl)-aminomethyl-phenyl]-2,2':6',2"-terpyridine (H2L4) which has never been reported has been synthesized. H2L4 is a zwitter ion salt in free state. A mononuclear RuⅢcomplex 22 with weak emission in room temperature has been synthesized by solution method using the precursor substance 4'-[4-N,N-bis(ethyl acetate)-aminomethyl-phenyl]-2,2':6',2"-terpyridine and RuⅢ. A mononuclear RuⅡcomplex 23 with decarboxylation of a carboxyl group has been synthesized by solution method. The mechanism of decarboxylation has been studied preliminarily. The emission property and lifetime has been investigated and showed that the energy transfer from ligand to the metal center was thoroughly for its strong phosphorescence with lifetime on microsecond level and without emission from ligand. Two complexes with 1D (24) structure and 3D double fold interpenetrated structure (25) have been synthesized by hydrothermal/solvothermal methods using H2LA ZnⅡand auxiliary ligands (oxalate/sodium oxalate). In the synthesis process of 24, there exists a hydrolysis reaction of DMF, which has been studied preliminarily.24 and 25 show excellent luminescence properties with lifetime on nanosecond level.25 has large voids and higher thermal stability and shows broad potential application prospects in functional materials.