Synthesis, crystal structure, thermal behavior, and fluorescence property of lanthanide complexes based on 2,6-dimethylbenzoic acid and 1,10-phenanthroline

Three dinuclear lanthanide complexes were prepared using 2,6-dimethylbenzoic acid and 1,10-phenanthroline as main ligand and auxiliary ligand, namely: [Eu(2,6-DMBA)(3)(phen)](2)(1), [Gd(2,6-DMBA)(3)(phen)(2)center dot 1.5H(2)O(2) and [Tb(2,6-DMBA)(3)(phen)](2)center dot 2.5H(2)O(3) (2,6-DMBA = 2,6-dimethylbenzoate; phen = 1,10-phenanthroline) and characterized by Raman spectroscopy, infrared spectroscopy, single crystal X-ray diffraction, elemental analysis and thermogravimetric analysis. Single-crystal X-ray diffraction shows that the three complexes were centered on 9 coordination Ln(III) ions and form a single hat tetragonal inverse prism geometry with surrounding nitrogen and oxygen atoms. The adjacent structural units form a 1D chain structure through C-H center dot center dot center dot O hydrogen bond interaction. TG-DSC/FTIR was used to study the thermal decomposition mechanism of the complexes and the main components of gases escaping during the decomposition process. Solid-state fluorescence studies showed that complexes 1 and 3 emitted strong red and green light, respectively. [GRAPHICS] .