Synthesis, structure and luminescence properties of two novel lanthanide complexes with 2-fluorobenzoic acid and 1,10-phenanthroline

Two lanthanide complexes with 2-fluorobenzoate (2-FBA) and 1,10-phenanthroline (phen) were synthesized and characterized by X-ray diffraction. The structure of each complex contains two non-equivalent binuclear molecules, [Ln(2-FBA)3 · phen · CH3CH2OH]2 and [Ln(2-FBA)3 · phen]2 (Ln = Eu (1) and Sm (2)). In [Ln(2-FBA)3 · phen · CH3CH2OH]2, the Ln3+ is surrounded by eight atoms, five O atoms from five 2-FBA groups, one O atom from ethanol and two N atoms from phen ligand; 2-FBA groups coordinate Ln3+ with monodentate and bridging coordination modes. The polyhedron around Ln3+ is a distorted square-antiprism. In [Ln(2-FBA)3 · phen]2, the Ln3+ is coordinated by nine atoms, seven O atoms from five 2-FBA groups and two N atoms of phen ligand; 2-FBA groups coordinate Ln3+ ion with chelating, bridging and chelating-bridging three coordination modes. The polyhedron around Ln3+ ion is a distorted, monocapped square-antiprism. The europium complex exhibits strong red fluorescence from 5D0 → 7F j ( j = 1–4) transitio...