Synthesis, crystal structure, and luminescence properties of new binuclear europium and terbium complexes with tubular morphology

The two dinuclear rare earth complexes Eu2(PBa)6(Phen)2 and Tb2(PBa)6(Phen)2, (where PBa = 4-pentylbenzoate group and Phen = 1, 10-phenanthroline), were synthesized and characterized by elemental analysis, IR, and single crystal X-ray diffraction. Both of them crystallize in space group P-1 with similar cell parameters. Each Eu or Tb ion is nine-coordinated with one 1, 10-phenanthroline molecule, one bidentate chelating carboxylate group, two bidentate bridging carboxylate groups, and two tridentate bridging carboxylate groups. The fluorescent properties of the europium and terbium complexes were also investigated. Under the UV excitation, the two complexes exhibit extensive characteristic emissions of europium and terbium ions, respectively.

► Two dinuclear rare earth complexes based on 4-pentylbenzoate group and 1, 10-phenanthroline were reported.
► The as-grown crystals show the tube-like morphology.
► The probable growth mechanism of the tubular crystals is proposed.
► The two complexes exhibit extensive characteristic emissions of europium and terbium ions, respectively.