Lanthanoid(Ⅲ) complexes containing bipyridinedicarboxylic acid ligand: Synthesis, spectroscopic characterization, thermal analysis, and crystal structures

Abstract

The present report deals with the synthesis of the two complexes of respective formula {[Ce(bpydcb)(HCOO)(H2O)]·H2O}n (1) and [Eu2(bpydcb)3(H2O)2(DMF)]·3H2O·0.5DMF (2) the structure of both of them elucidated by single-crystal X-ray diffraction and powder X-ray diffraction to demonstrated that complexes 1 and 2 crystallize in a similar space group P21/c as a monoclinic system with high crystal purity. X-ray Single crystal diffraction analysis demonstrates, nine-coordinate environment of Ce (Ⅲ) in the complex 1 and octa-coordinate environment of Eu (Ⅲ) in the complex 2. And discovered the tricapped trigonal prism of cerium complex and the triangular dodecahedron of europium complex. Meanwhile, the complexes were characterized by elemental, infrared, ultraviolet, fluorescence and thermal analysis. Fluorescence testing shows that complex 1 emits ligand fluorescence, while complex 2 emits fluorescence from the ligand to the central ion, emitting characteristic fluorescence of europium ion, both complexes can emit strong fluorescence. The thermogravimetric analysis results show that the thermal stability of complex 1 is better than that of complex 2, and its organic framework only begins to collapse after 375 ℃.