1-(Pyridin-2-ylmethyl)-2-(3-(1-(pyridin-2-ylmethyl)benzimidazol-2-yl) propyl) benzimidazole and its copper(II) complex as a new fluorescent sensor for dopamine (4-(2-aminoethyl)benzene-1,2-diol)

A new ligand 1-(pyridin-2-ylmethyl)-2-(3-(1-(pyridin-2-ylmethyl)benzimidazol-2-yl) propyl) benzimidazole (L) and its Cu(II) complex (1) have been synthesized and characterized spectroscopically and structurally. The Cu(II) ion is coordinated by two nitrogen atoms of benzimidazole groups, two oxygen atoms of the nitrate anions and one oxygen atom of a water molecule forming distorted trigonal bipyramidal geometry. The ligand and its complex have been utilized as a fluorescent sensor for 4-(2-aminoethyl)benzene-1,2-diol. A plot of F0/F − F0 vs 1/Conc (4-(2-aminoethyl)benzene-1,2-diol) at a selected wavelength of 306 nm with (L) that shows a straight line behavior, supports the validity of the assumption of 1:1 complex formation and the association constant of (L) with 4-(2-aminoethyl)benzene-1,2-diol is calculated to be 9868 M− 1. Sensor (L) is found to be selective for 4-(2-aminoethyl)benzene-1,2-diol over aromatic amines, phenols, amino catechol (L-3,4-dihydroxyphenylalanine) and 4,6-ditertiarybutyl benzene-1,2-diol.

A new ligand N-picolylated bis-benzimidazolyl ligand (L) and its copper(II) complex have been synthesized, characterized spectroscopically and structurally. The geometry of Cu(II) is distorted in trigonal bipyramidal. The ligand and the complex have been utilized as a florescent sensor for dopamine. A new band generated with ligand is due to the formation of a host guest complex formed between pyridine moiety and dopamine. Sensor (L) is selective to the compounds bearing both the amino and phenolic moiety, as is the case with dopamine.Figure optionsDownload as PowerPoint slideHighlights
► New bis benzimidazole ligand has been synthesized and characterized structurally.
► Cu (II) complex of the ligand has been synthesized and characterized structurally.
► The ligand and its complex have been utilized as a fluorescent sensor for dopamine.
► Ligand is found to be selective for dopamine over aromatic amines and phenols.