Studies On The Structure Regulation And Lumineseent Properties Of Lanthanide Complexes

The design and assembly of lanthanide coordination polymers have been of considerable interest because of their potential applications, such as gas storage, sensor, separation, catalysis, ion exchange, and other materials applications. In addition, lanthanide ions can exhibit excellent photophysical properties; especially, Sm(Ⅲ), Eu(Ⅲ), Tb(Ⅲ), and Dy(Ⅲ) are, in general, considered to have the brightest emission with some organic ligands, which play a vital role in sensors, liquid crystalline materials, or luminescent labeling reagents for specific biomolecular interactions. Our group has been interested in employing self-assembly strategies for lanthanide complexes and has recently selected amide type ligands as organic molecular building blocks to construct the novel and satisfactory luminescent lanthanide complexes. To confirm how different anions, lanthanides'radii, different terminal groups influence supramolecular self-assembly of lanthanide complexes as well as their luminescent properties, seven amide type ligands and their lanthanide complexes were designed and synthesized. The luminescent properties of lanthanide complexes are also investigated in detail.The thesis is divided into five parts:1. A brief review of investigation progress of the crystal structures and luminescent properties of the lanthanide complexes was summarized.2. Lanthanide coordination polymers{[Ln2L3Ⅰ(NO3)6]·nH2O}n (Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Er. n=0except for Pr with n=4and Nd with n=7.) have been assembled using lanthanide nitrates and an amide type semirigid bridging ligand, LⅠ, as building blocks. The crystal structures of the complexes{[Pr2L3Ⅰ(NO3)6]·4H2O}n,{[Nd2L3Ⅰ(NO3)6]·7H2O}n,[Sm2L3Ⅰ(NO3)6]n,[Eu2L3Ⅰ(NO3)6]n,[Tb2L3Ⅰ(NO3)6]n, and [Er2L3Ⅰ(NO3)6]n were determined by single-crystal X-ray diffraction. Interestedly,{[Pr2L3Ⅰ(NO3)6]·4H2O}n and {[Nd2L3Ⅰ(NO3)6]·7H2O}n demonstrate unusual lanthanide porous noninterpenetrated honeycomb-like (6,3) topology frameworks, while [Sm2L3Ⅰ(NO3)6]n,[Eu2L3Ⅰ(NO3)6]n,[Tb2LⅠ3(NO3)6]n, and [Er2L3Ⅰ(NO3)6]n exhibit novel one-dimensional linear coordination polymeric structures. Their structural variations are attributed to lanthanide contraction effect. The luminescent properties of Sm(Ⅲ), Eu(Ⅲ), Tb(Ⅲ), and Dy(Ⅲ) complexes are also investigated in detail. The lowest triplet state (T1) energy level of this ligand matches better to the lowest resonance energy levels of Tb(III) and Dy(III) than Eu(III) and Sm(III) ions.3. To confirm how different anions influence supramolecular self-assembly of lanthanide complexes as well as their luminescent properties, two new flexible amide type ligands, LⅡ and LⅢ and their lanthanide nitrate and picrate complexes have been designed and assembled.{[EuLⅡ (NO3)3]-1.5CHCl3}n demonstrates an unprecedented chiral noninterpenetrated two-dimensional (2-D) honeycomb-like (6,3)(hcb, Schlafli symbol63, vertex symbol6-6-6) topological network, and [EuL (pic)3]n confirms an unusual chiral LnOF with three-dimensional (3-D)(10,3)-a (srs, SrSi2, Schlafli symbol103, vertex symbol102·104·104) topological framework.[Ln2LⅢ2(NO3)6(DMF)2]n [Ln=Pr, Sm, Eu, Tb, and Dy] have zero-dimensional (OD) dinuclear rectangular macrocycle architectures, while the [LnLm(pic)3(CH3CH2OH)]n [Ln=Nd, Eu, Tb, and Er] exhibit one-dimensional (1D) chain pattern. The variations of the coordination structures are attributed to different steric confinement of the nitrate and picrate anions. Also the anion-induced structures and energy transfer processes in the luminescence behavior of lanthanide complexes were discussed in detail.4. To explore the effect of terminal groups of ligands on the structure and photoluminecence behaviors of the complexes, we have designed and synthesized a amide type ligand LⅣ and its lanthanide complex. The coordination polymer type {[Eu2LⅣ3(NO3)6]·CH3COOC2H5·CH3OH}n possesses an unusual ladderlike double chain. Compared with the complexes having one-dimensional zig-zag coordination polymer which was previously reported by Yi et al, we discussed the difference of the two kind of structures and luminescent properties.5. We have designed and synthesized three amide type ligand LⅤ～LⅦ and their lanthanide complexes. The ligands and complexes have been synthesized and characterized by1H NMR, elemental analysis, IR spectra, X-ray crystal structure analysis, luminescence spectra and phosphorescence spectra.The ligands are listed below:1,3-bis{[(2'-benzylaminoformyl)phenoxyl]methylbenzene (LⅠ)1,1,1-tris-{[(2'-benzylaminoformyl)phenoxyl]methyl}ethane (LⅡ)benzyl-N,N-bis[(2'-benzylaminofomyl)phenoxyl)ethyl]-amine (LⅢ)1,4-bis{[2'-furfurylaminoformyl)phenoxyl]methyl}naphthalene (LⅣ)1,5-bis{[(2'-(2-picolylaminoformyl))phenoxyl]methyl} naphthalene (LⅤ)2,3-bis{[(2'-furfurylaminoformyl)phenoxyl]methyl}quinoxalinone (LⅥ)1,1,1-tris-{[(2'-m-picolylaminoformyl)phenoxyl]methyl} ethane (LⅦ)...