Five Dinuclear Lanthanide Complexes Based on 2,4-dimethylbenzoic Acid and 5,5′-dimethy-2,2′-bipyridine: Crystal Structures, Thermal Behaviour and Luminescent Property

A series of new complexes, [Ln (2,4-DMBA) 3 (5,5′-DM-2,2′-bipy)] 2 (Ln = Sm(1), Eu (2)), [Pr (2,4-DMBA) 3 (5,5′-DM-2,2′-bipy)] 2 ·0.5(C 2 H 5 OH) (3), [Ln (2,4-DMBA) 3 (5,5′-DM-2,2′-bipy)] 2 ·0.5(2,4-DMBAH)·0.25(5,5′-DM-2,2′-bipy) (Ln = Tb (4), Dy (5)) (2,4-DMBA = 2,4-dimethylbenzoate, 5,5′-DM-2,2′-bipy = 5,5′-dimethy-2,2′-bipyridine) were synthesized via hydrothermal reaction conditions. The complexes were characterized through elemental analysis, Infrared spectra (IR), Raman (R) spectra, UV-Vis spectra, single X-ray diffraction. Single crystal data show that complexes 1 – 5 are binuclear complexes, but they can be divided into three different crystal structures. The thermal decomposition mechanism of complexes 1 – 5 were investigated by the technology of simultaneous TG/DSC-FTIR. What’s more, the luminescent properties of complexes 1 – 2 and 4 were discussed, and the luminescence lifetime (τ) of complexes 2 and 4 were calculated.