The study of metal binding properties and electronic transitions of dithienopyrole derivatives

Abstract

Fluorescence chromophore (L) based on dithienopyrole derivatives (DPT) have been compared the binding site for detecting metal ions. There are consisting of methacryloyl amine (L1) and cyanoacrylic acid (L2) acceptor, respectively. Corresponding molecular geometries, orbital energies, electron contributions and absorption properties of the fluorescence sensor were investigated by using density functional theory (DFT) with B3LYP method of calculation. The DFT based studies with various solvation and absorption spectra were performed using time-dependent density functional theory (TD-DFT) with the polarized continuum model. Comparing with L2, the experimental L1 shows a red shift both absorption and emission spectra at 350 and 485 nm, respectively. The solvent environment exhibited slight shift in experimental and calculated absorption. An effect of various metal ions on absorption behavior was studied. Results indicate that the L1 and L2 exhibit excellent sensitivity for Pb2+ ion. The binding complex M-L1 and M-L2 (M: Cd, Cu, Hg, Pb, Zn) exhibited Pb<Cu<Zn<Mn<Cd<Hg.