Synthesis, Crystal Structure And Optical Property Of The RE-Aromatic Carboxylic Acid Complexes

The complexes of rare earth and aromatic carboxylates exhibited novel structure, especial efficiency of optics, electricity and magnetism, and exhibited great applied value in material chemistry. The research of synthesis, crystal structure and optical property of the RE-aromatic carboxylic acid complexes had important significance for obtaining the optimum of synthesis, constructing supramolecular structure and developmenting the new application value of the rare earth aromatic carboxylates, so it had become one of hot topics of the coordination chemistry and material chemistry. In this paper, the rare earth ions(Re=Dy3+, Er3+, Eu3+, Ce3+, La3+) were chosen to be the central ions, and salicylic acid, acetylsalicylic acid,1,4-benzenedicarboxylic acid,1,10-phenanthroline were chosen to be ligands. The rodlike binary complexes Re2(sal)6·8H2O(Re=Dy, Er), the sphere ternary complexes Re(sal)3phen2(Re=Eu, Ce) and the leaves shape binary complex La2(1,4-bdc)2-3H2O were successfully synthesized by hydrothermal method. The composition, crystal structures, morphylogies, sizes and properties of the obtained products were determined by Elemental analysis (EA), Fourier transform infrared spectrum (FTIR), Thermal analysis (DSC-TGA), X-ray single crystal diffraction (XRD), Scanning electron microscope (SEM) and Fluorescence spectrophotometer (FS), respectively. There is the main content as follows.(1) The rodlike binary complexes Re2(sal)6·8H2O(Re=Dy, Er) were synthesized by hydrothermal method. The results showed that the crystal structure of Dy2(sal)6-8H2O belongs to triclinic, space group P1with a=9.4759(10) A, b9.9656(10) A, c=14.353(2) A, α=99.098(2)°, β=91.569(2)°, γ=115.9130(10)°, Z=1, V=1196.7(2) A3, F(000)=638. A comparative study of optical properties of salicylic acid and Dy2(sal)6·8H2O, found that the fluorescence intensity of the complex was lower than salicylic acid. The results showed that the crystal structure of Er2(sal)6·8H2O belongs to triclinic, space group P1with a=9.4748(13) A, b9.9698(14) A, c=14.379(2) A, α=99.076(2)°,β=91.643(2)°, γ=115.753(2)°, Z=1, V=1200.8(3) A3, F(000)=642. A comparative study of optical properties of salicylic acid and Er2(sal)6·8H2O, found that the fluorescence intensity of the complex was higher than salicylic acid.(2) The sphere ternary complexes Re(sal)3phen2(Re=Eu, Ce) were synthesized by hydrothermal method. The results showed that the crystal structure of Eu(sal)3phen2belongs to monoclinic, space group P21/c with a=17.4563(16) A, b=12.6117(11) A, c=23.4867(15) A, α=90°,β=131.817(4)°,γ=90°, Z=4, V3853.6(5) A3, F(000)=1856. A comparative study of optical properties of salicylic acid and Eu(sal)3phen2complex, found that the complex exhibited a blue-shift and the fluorescence quenching. The results showed that the crystal structure of Ce(sal)3phen2belongs to monoclinic, space group P21/c with a=16.1206(16) A, b=10.9218(11) A, c=22.380(2) A,α=90°, p=90.026(2)°,γ=90°, Z=4, V=3940.4(7) A3, F(000)=1836. A comparative study of optical properties of salicylic acid and Ce(sal)3phen2complex, found that the complex exhibited a blue-shift and the fluorescence quenching.(3) The leaves shape La2(1,4-bdc)2·3H2O was synthesized by hydrothermal method. The results showed that the carboxylate oxygen atoms from terephthalic acid were coordinated with La3+ions. And the size range of the leaves shape micron complex was1-3μm according to the SEM of this complex.