Synthesis and structural characterization of lanthanide metal complexes by 2-fluorobenzoic acid with 2,2′:6′,2″-terpyridine, and their fluorescence properties

•Three new Ln(Ⅲ) complexes were synthesized and structures were characterized.•Mononuclear and binuclear were assembled into supramolecular structures.•X-ray crystal structure and the infrared spectrum.•Dy3+ and Tb3+ complexes show luminescence of the trivalent lanthanides.•The thermal decomposition mechanism was investigated by TG-DSC/FTIR. Three new lanthanide complexes were synthesized by conventional solution synthesis at room temperature with the formula of [Ln(2-FBA)2(terpy)(NO3)(H2O)]·(terpy)·H2O(Ln=Dy(1)), [Ln(2-FBA)3terpy]2·2(2-FHBA)·2H2O(Ln=Pr(2),Tb(3)), (2-FBA=2-fuorobenzoate, terpy=2,2′:6′,2″-terpyridine). The complexes were characterized by elemental analysis, X-ray single crystal diffraction and infrared spectroscopy. The coordination number of complexes 1–3 is 9, showing a muffin geometry. Complex 1 is mononuclear, crystallized in the monoclinic system and space group P21/c . Complexes 2 and 3 are binuclear molecules of isomorphous, and their adjacent structural units form 1D chain and 2D sheets structure through C-H···F hydrogen bonding and π-π stacking interactions. In addition, the solid state fluorescence spectra of complexes 1 and 3 were measured. The test shows that complex 3 emits strong green light. The thermal decomposition mechanism of the complexes was studied by synchronous thermal analyzer infrared spectroscopy TG-DSC/FTIR and the 3D stacked plots of the escape gases were analyzed.