Self-assembled coordination nanoparticles from nucleotides and lanthanide ions with doped-boronic acid-fluorescein for detection of cyanide in the presence of Cu2+ in water

The sensor molecule, F-oBOH, containing boronic acid-linked hydrazide and fluorescein moieties was synthesized. For anion sensing applications, F-oBOH was studied in aqueous media. Unfortunately, F-oBOH was found to be hydrolyzed in water. Therefore, a new strategy was developed to prevent the hydrolysis of F-oBOH by applying self-assembly coordination nanoparticles network (F-oBOH-AMP/Gd3+ CNPs). Interestingly, the nanaoparticles network displayed the enhancement of fluorescent signal after adding Cu2+ following by CN−. The network, therefore, possessed a high selectivity for detection of CN− compared to other competitive anions in the presence of Cu2+. Cyanide ion could promote the Cu2+ binding to F-oBOH incorporated in AMP/Gd3+ CNPs to give the opened-ring form of spirolactam resulting in the fourfold of fluorescence enhancement compared to Cu2+ complexation without CN−. Additionally, the log K value of F-oBOH-AMP/Gd3+ CNPs⊂Cu2+ toward CN− was 3.97 and the detection limits obtained from naked-eye and spectrofluorometry detections were 20 μM and 4.03 μM, respectively. The proposed method was demonstrated to detect CN− in drinking water with high accuracy.