UV-vis and theoretical studies on an ensemble of dinuclear Cu(II) complex of anthracene-based tripodal tetramine with pyrogallol red for cyanide detection and species distribution in aqueous solution

摘要

In this research, we synthesized the dinuclear Cu(II) complex of anthracene based tripodal tetramine (Cu(2)L1) which formed an ensemble with pyrogallol red (PGR, denoted by L2). This ensemble showed a selective colorimetric sensing ability towards cyanide ion by changing color from blue to colorless. Combining UV-vis titration and TD-DFT calculations, the sensing mechanism was proved to be not related with indicator displacement assays (IDAs) as most ensemble systems, but it occurred through Cu(2)L1 induced the nucleophilic addition of cyanide to PGR unit of the ensemble. All calculation and simulation results indicated that [CN/L2/Cu(2)L1/L2/CN](2-) was found to be dominant species in the equilibrium mixtures of the titrating solutions. The detection limit of cyanide of 0.029 ppm for the system in 20% (v/v) water-acetonitrile buffered at pH 7.4 with HEPES was found. This ensemble system for detection of cyanide anion with high sensing in real water samples was suggested.