Synthesis, structures, photoluminescence and magnetic properties of three dinuclear lanthanide(III) complexes derived from 4-fluorophenylselenoacetic acid

Three novel dinuclear lanthanide(III) complexes [Ln(2)L(6)(phen)(2)] (Ln=Eu-III (1), Tb-III (2), Dy (III) (3)), derived from 4-fluorophenylselenoacetic acid and 1,10-phenanthroline, have been synthesized and characterized by elemental analysis, IR, TGA, powder X-ray diffraction and single-crystal X-ray diffraction analysis. Single crystal X-ray diffraction reveal they are isostructural and crystallize in the monoclinic crystal system, space group P2(1)/c. The investigations on luminescent properties of Eu(III) complex 1 and Tb(III) complex 2 exhibit the characteristic emissions of Eu-III (D-5(0)-> F-7(0-4)) and Tb-III (D-5(4)-> F-7(6-3)), and the corresponding luminescent lifetimes are 1.52 and 1.10 ms, respectively. Temperature-dependent photoluminescence studies show the emission intensities and lifetimes for both complexes decrease upon increasing temperature, which indicates complexes 1 and 2 have the potential for sensing temperature. The magnetic studies reveal that Dy(III) complex 3 exhibits weak antiferromagnetic interactions and slow magnetic relaxation behavior.