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

Two dimeric rare earth complexes [Eu(m-MOBA)3(phen)]2 (I) and [Tb(m-MOBA)3(phen)]2·2C2H5OH (II) (where m-MOBA = m-methoxybenzoate, phen = 1,10-phenanthroline) were synthesized and structurally characterized. Both complexes consist of neutral dimeric molecules. Complex I crystallizes in triclinic system, space group P1¯. Each Eu(III) ion is nine-coordinated with one 1,10-phenanthroline molecule, one bidentate chelating carboxylate group, two bridging bidentate carboxylate groups and two bridging tridentate chelating carboxylate groups. Complex II crystallizes in triclinic system, space group P1¯. Each Tb(III) is eight-coordinated with one 1,10-phenanthroline molecule, one bidentate chelating carboxylate group and four bridging bidentate carboxylate groups. Complex I shows bright red luminescence, II shows green luminescence under UV light at room temperature, respectively. The thermal analysis indicates that they are all quite stable to heat.