Synthesis, Structure, Photoluminence And Visible Light Photocatalytic Properties Of Complexes Based On Schiff Base And Aromatic Multiple Acid Ligands

Some new functional coordination compounds were synthesized byhydrothermal and solution methods using schiff base and aromatic multiple acids asdifferent organic ligand, and rare earth ions and titanium ion as the central atoms.And then these complexes were characterized and the results indicate that thecomplexes show novel structure and the unique properties. This article is composedof three parts.（1） We choose5-sulfoisophthalic acid monosodium salt as first ligand,1,10-phenanthroline as second ligand to synthesize Dy and Tb, Sm single rare earthbased complexes as well as the Gd and Tb double rare earth based complexes bysolution method. The formula of the molecular structure was deduced by structuralcharacterization, and the solution fluorescence properties of composition weremeasured. The results indicate that the different rare earth ions have differenteffects on fluorescence of the complexes with the same ligands. The “concentrationeffect” of heteronuclear structure obviously strengthes the fluorescence of the rareearth complexes.（2） We choose2-aminobenzothiazole to react with salicylaldehyde and orthovanillin respectively to form schiff bases. The structure of the schiff base wascharactered by IR, elemental analysis and X ray diffraction, and the reaction of theschiff base with the rare earth ions resulted in complexes, the solution fluorescenceof which was investigated, and the results indicate that, in contrast to ligand, theemission peak of the complexes has blue shift to100nm, and their excitation andemission intensity also decreased obviously.（3）We choose p-phthalic acid and tetrabutyl titanate as raw materials. Severalmetal-organic frameworks （MOFs） doped with different proportions of Fe³⁺weresynthesized by hydrothermal method. By calcining the MOFs acting as theprecursors, TiO₂was synthesized. The MOFs and the prepared TiO₂were comparedby the characterization of XRD, XPS, SEM, BET, UV-vis and the photochemicalcatalysis. The result indicate that, compared with calcining-resulted TiO₂, MOFs precursors has smaller grain size, bigger surface area and well-defined surfacemorphology, however lower visible light photocatalytic activity, due to higherband-gap energy.Although, after calcining, the resulted TiO₂has collapsed poresand small BET values, the photocatalytic activities are enhanced, and the bindingstrength between TiO₂nanoparticles becomes stronger, furthermore, doping Fe isbeneficial for promoting binding strength and separation of particles from solutionbecome easier.