Synthesis And Properties Of The Organic Nitrogen Rare Earth Complexes

Rare earth luminescent materials, especially europium complexes have attracted widely attention. N-benzoyl-phthalimide was synthesized by replacing the N atom of phthalimide, then it coodinated with rare earth to prepar rare earth complexes, and the complexes were explored the structure and fluorescence properties.1. With homemade benzoyl choride and phthalimide potassium as raw materials, preparation of N-benzoyl-phthalimide(referred NBP), yield was15%. Using infrared spectroscopy(FT-IR), hydrogen nuclear magnetic spectroscopy(1HNMR) characterize structure.2. Binary complex was synthesized by reacting EUCl3and NBP, discussing fluorescence spectra of complex at different feeding ratio and different reaction temperature, the results show that optimum reaction temperature is50℃and feeding ratio of n(EuCl3):n(NBP)=1:2. Then the factors of synthetic process conditions (reaction temperature and feeding ratio), different pH and metal ions on fluorescence intensity was studied. When the reaction temperature is50℃, n(EuCl3):n(NBP)=1:2, the fluorescence intensity of this complex is the largest and best efficiency. The larger luminous intensity range of pH is5～7, the best pH is6.24, if pH below or above this value, the fluorescence intensity of the complex will reduce. Cr3+and Pb2+have little effect on fluorescence intensity, while Ni2+and Fe3+have a large impact on it, among this, Fe3+has a great impact on fluorescence intensity, Fe+has a quenching effect on fluorescence of this complex.3. Through the experiment and analysis, it can be drawn that the optimum reaction temperature of Eu-NBP-phen complex is60℃, the best material ratio n(Eu3+) n(NBP):n(phen)=1:2:1, the best feeding order is that adding NBP first then join phen, only in this way the fluorescence intensity of the complex is the strongest. Then factors of different pH, different metal ions and different concentration of Fe3+on the fluorescence intensity were investigated. When the pH is less than6, the fluorescence intensity of this complex is very low, within range of6～7, the fluorescence intensity reaches maximum, when pH is greater than7, the intensity decreases instaed. Cr3+and Pb2+have smaller influence on luminescence, while Ni2+and Fe3+have a large effect, which Fe3+has a largest effect on luminescence. Thus, Fe3+has a great quenching effect on this complex.4. Different amounts of La3+were added into Eu-NBP-phen, the results indicate that the incorporation of a certain amount of La3+can increase the fluorescence intensity of the complex. When proportion of La3+/Eu3+is0.3/0.7, the fluorescence intensity is the largest, more than the value of0.3/0.7, the intensity decreases instead, the optimum incorporation ratio of La3+is La3+/Eu3+=0.3/0.7.