Lanthanide Complexes Based on Rigid Benzimidazole Carboxylic Acid Ligand: Sensing of Nitrobenzene, Fe(III) Ions, and Adsorption of Dyes

Five new lanthanide complexes {[Sm(H2L)(H2O)4(Cl)]& sdot;H2O & sdot;Cl}n (1), {[Eu(H2L)(H2O)4Cl]& sdot;Cl}n (2), {[La(H2L)(H2O)4Cl]& sdot;Cl}n (3), {[Pr(H2L)(H2O)4Cl]& sdot;Cl}n (4), {[Ce(H2L)(H2O)4Cl]& sdot;Cl}n (5) (H3L = 2-hydroxy-5-(5-(hydroxy-lambda 2-methoxy)-1H-benzo[d]imidazole-5-carboxylic acid) were successfully synthesized under solvothermal method. 1 exhibits a two-dimensional (2D) network structure, whereas 2-5 feature one-dimensional (1D) chain structure. The fluorescence investigations demonstrated that 1-5 could be the fluorescent sensor for nitrobenzene (NB) and Fe(III) ions with high selectivity, sensitivity, and low detection limits. Furthermore, 1-5 displayed the good adsorption to anionic dye Congo red (CR), and the adsorption capacities were 140.5, 206.5, 212.5, 111.5, and 211.5 mg<middle dot>g-1, respectively. Five new lanthanide complexes were synthesized. The fluorescence investigations demonstrated that 1-5 could be the fluorescent sensor for NB and Fe(III) ions with high selectivity, sensitivity, and low detection limits. Furthermore, 1-5 displayed the good adsorption to anionic dye Congo red (CR).image