Synthesis, structures and properties of ternary rare earth complexes with fluorobenzoic acid and 1,10-phenanthroline

Abstract

Three dimeric rare-earth complexes [Eu(p-FBA)₃(phen)(H₂O)]₂ (1), [Tb(p-FBA)₃phen]₂ (2), and [Tb(o-FBA)₃phen]₂ (3) (where p-FBA = p-fluorobenzoate, o-FBA = o-fluorobenzoate, phen = 1,10-phenanthroline) were synthesized and structurally characterized. All are neutral dimeric molecules. Complex 1 crystallizes in triclinic system, space group P 1. Each Eu(III) ion is eight-coordinate with one 1,10-phenanthroline, one monodentate carboxylate, one water and four bridging carboxylates. Complex 2 crystallizes in triclinic system, space group P 1. Each Tb(III) is also eight-coordinate with one 1,10-phenanthroline molecule, one bidentate chelating carboxylate and four bridging carboxylates. Complex 3 crystallizes in the monoclinic system, space group P2₁/c and consists of two crystallographically different binuclear molecules. Tb(III) ions are eight-coordinate with one 1,10-phenanthroline, one bidentate chelating carboxylate and four bridging carboxylates in both of them. Complex 1 shows bright red luminescence, 2 and 3 show green luminescence under UV light at room temperature. Thermal analysis indicates that are all quite stable to heat.

Keywords:

• Terbium complex
• Europium complex
• Crystal structure
• Luminescence
• Fluorobenzoic acid
• 1,10-Phenanthroline

Acknowledgements

This work was supported by the Natural Science Foundation of Hebei Province (No. 203148) and Hebei Education Department (No. 2006125), P.R. China.