Highly Thermostable One-Dimensional Lanthanide(III) Coordination Polymers Constructed from Benzimidazole-5,6-dicarboxylic Acid and 1,10-Phenanthroline: Synthesis, Structure, and Tunable White-Light Emission

Abstract

Three novel isostructural lanthanide(III) coordination polymers (LnCPs), {[Ln3(bidc)4(phen)2(NO3)]·2H2O}n (Ln = Gd (1), Eu (2), Tb (3); H2bidc = benzimidazole-5,6-dicarboxylic acid, and phen = 1,10-phenanthroline), were synthesized via hydrothermal reaction and characterized. The complexes crystallize in the chiral space group P212121. They possess 1D structures based on lanthanide trinuclear clusters containing Ln(1)O9, Ln(2)O6N2, and Ln(3)O6N2 polyhedra by bidc linkers, and phen and nitrate act as terminal ligands. The bidc and phen ligands provide efficient energy transfer for the sensitization of Eu(III) and Tb(III) complexes. The complexes 2 and 3 emit red and green light, respectively. Lifetimes and quantum yields of luminescence are 0.86 ms and 13.20% for 2 and 0.32 ms and 2.08% for 3. Tuning of white-light emission by adjusting the doping concentration of Eu(III) and Tb(III) ions in the Gd(III) complex was achieved.