Studies On The Supramolecular Rare Earth Complexes With Novel Multipodal Ligands And Their Composite Luminescent Materials

Partâ… The design and synthesis of functional complexes with novel structure have attracted much attention in the supramolecular chemistry. Rare earth elements are a group of special inorganic ions with good luminescent, electronic and magnetic properties, and the assembling of rare earth supramolecular complexes with specific spectroscopic, electric and magnetic properties is challenging for their high and variable coordination number. Multipodal ligands have the merits in adjustable structure and changeable terminal groups, which make their rare earth complexes, have novel structures and good luminescence properties. In this dissertation, twelve kinds of new amide type multipodal ligands using N-benzylsalicylamide or salicylaminomethylpyridine as terminal group and their rare earth complexes have been synthesized and characterized by elemental analysis, molar conductance, IR spectra, ¹HNMR, electronic spectra and X-ray crystal structure analysis. The results show that these ligands can form stable complexes with rare earth ions and coordinate with the central ions in multi-monodentate coordination mode. Studies on the luminescent properties of the complexes indicate that N-benzylsalicylamide or salicylaminomethylpyridine terminal group like salicylic acid has good antenna effect to the metal ions. The luminescence of Tb³⁺ complexes is much stronger than that of Eu³⁺ complexes. It is suggested the lowest triplet-state energy of the ligands matches better to Tb³⁺ than to Eu³⁺. The skeleton structure, terminal groups, the numbers of branched chains and the counter anion all have influence on the luminescent properties of the complexes.The ligands involved in this part are listed below:benzyl-N, N-bis[(2'-benzylaminofomyl)phenoxyl)ethyl]-amine (L¹)benzyl-N, N-bis[(3'-pyridinylmethylaminoformyl)phenoxyl)ethyl]-amine(L²)benzyl-N, N-bis[(2'- benzylaminofomyl)phenoxyl)ethyl]-amine (L³)ethyl-N, N-bis[(2'-benzylaminofornyl)phenoxyl)ethyl]-amine (L⁴)1,2-bis{N,N-bis[(2'-benzylaminoformyl)phenoxyl)ethyl]amino}ethane(L⁵){{N,N-bis[(2'-benzylaminoformyl)phenoxyl)ethyl]amino}diphenyl}methane(L⁶)1, 3, 5-trimethyl-2, 4-bis{{N,N-bis[(2'-benzylaminoformyl)phenoxyl)ethyl]amino}-methyl}benzene(L⁷) 1,2,4,5-tetramethyl-3,6-bis{{N,N-bis[(2'-benzylaminoformyl)phenoxyl)ethyl]amino}-methyl}benzene(L⁸)1,1, 1-tris{[(2'-benzylaminoformyl)phenoxyl]methyl}propane(L⁹)2,2', 2"-nitrilotris(2-benzylaminoformyl)phenoxy)triethylamine (L¹⁰)2,2', 2"-nitrilotris(3'-pyridinylmethylaminoformyl)phenoxyl)triethylamine (L¹¹)2,2', 2"-nitrilotris(2'-pyridinylmethylaminoformyl)phenoxyl)triethylamine (L¹²)Partâ…¡The applications of the rare earth complexes are limited by the poor optical, thermal and chemical stabilities. Stable inorganic solid matrices which can change the structure and chemical microenvironment of guest molecules or ions, could affect the luminescent properties of guest molecules or ions distinctly. So the hybrid of the rare earth complexes with suitable inorganic solid matrices is a desirable way to improve the luminescent properties and the stabilities of the complexes, develop novel rare earth luminescent materials and widen their application field. Till now the works are mainly concentrated on single inorganic matrix such as SiO₂ gels. But conventional gels tend to crack during the drying period owing to their poor mechanical strength. One strategy is to introduce polymer or organic into inorganic matrix and the obtained polymer /inorganic hybrids exhibit notable mechanical strength and optical properties. We inserted carboxylic acid rare earth luminescent complexes into a sol-gel derived SiO₂ or PVB/SiO₂ matrix and obtain novel rare earth complex matrix composite luminescent materials. The results show that the obtained composite luminescent materials have better luminescent properties than those of the corresponding rare earth complexes. We deduce that this result comes from the effects of the supramolecular interaction between the host matrix and the guest complexes, the porous network structure of the assemblies and dispersive, isolation and protection action of the matrices. Moreover, the content of the complexes and PVB can also affect the luminescent properties of the composite materials to a certain extent.The ligand involved in this part is listed below:3, 6-bis [(4'-carboxyphenoxy) methyl]-1, 2,4, 5-tetramethylbenzene (H₂L¹³)...