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

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.