Preparation, Characterization And Luminescence Properties Of Eu(Ⅲ) And Ru(Ⅱ) Complexes Covalently-grafted Hybrid Materials

Rare earth (RE) complexes have been well known to give sharp, intense emission lines upon ultraviolet light irradiation because the effective intramolecular energy transfers from the coordinated ligands to the luminescent central lanthanide ions, which in turn undergoes the corresponding radiative emitting process. Ruthenium(II) complexes also have stable photophysical property and high thermal stability. However, poor photostability limits their practical application. Recently, because their photophysical properties could be modified by interaction of the host structure, the luminescence properties of RE complexes and Ruthenium(II) complexes supported on a solid matrix were studied extensively. Among them, the mesoporous molecular sieves used as a support for RE complexes and Ruthenium(II) complexes have attracted particular attention.In this paper, the dissertation is focused on the preparation and characterization of various silica-based mesoporous hybrid materials covalently grafted with Eu(III) complex. Detailed analyses on the matrix structure, stability, and photostability of the final obtained mesoporous hybrid materials are investigated. We have designed and synthesized the 2-phenyl-1H-imidazo [4,5-f] [1,10]phenanthroline functionalized hydrolysable compounds with double functions, i.e., as the second ligand of Eu(III) complexe and as the precursor of the sol-gel process. The covalently-grafting of the organic components to the inorganic framework can be achieved via the hydrolyzation and co-condensation reactions between the TEOS and the as-synthesized compounds. The photostability of the Eu-MCM-41 is superior to those of the pure europium complex and that physically incorporated in MCM-41.On the basis of oxygen sensing materials consisted of Ruthenium(II) complexes covalently grafted to mesostructured MCM-41, we also studied its pH senstive fluorescent behavior. The applicability of the principle of direct of covalently-grafting mesoporous material in the development of pH luminescent chemical sensing materials is decreased with the increasing pH. The pH sensing properties of this kind of covalently-grafted functionalized mesoporous powder materials can be further improved via changing the miscrostructure of the supports.