Synthesis, crystal structure, and fluorescence of two dimeric europium(III) complexes with 2-(trifluoromethyl)benzoate

Abstract

Two complexes [Eu 2(2-TFMBA) 6(2,2'-bipy) 2]·2H 2O ( 1) and Eu 2(2-TFMBA) 6(1,10-phen) 2 ( 2) (2-TFMBA=2-(Trifluoromethyl) benzoate; 2,2'-bipy=2,2'-bipyridine; 1,10-phen=1,10-phenanthroline) were synthesized by solvent method and determined by X-ray diffraction analysis. Complex 1 crystallizes in monoclinic system with space group P2 1/ c, whereas complex 2 crystallizes in triclinic system with space group ▪. Both are binuclear molecules with an inversion center. In complex 1, two center Eu 3+ ions are linked together by four 2-TFMBA ligands in bidentate-bridging mode. Each Eu 3+ ion is eight-coordinated with six O atoms from five 2-TFMBA ligands and two N atoms from one 2,2'-bipy molecule. In complex 2, two center Eu 3+ ions are linked together by four 2-TFMBA ligands in two modes, namely, bidentate-bridging and tridentate-bridging. Each Eu 3+ ion is nine-coordinated with seven O atoms from five 2-TFMBA ligands and two N atoms from one 1,10-phen molecule. The two complexes both exhibited strong red fluorescence under ultraviolet light, and the 5D 0 → 7F j ( j=0–4) transition emissions of Eu 3+ ion were observed in their emission spectra.