Synthesis, characterization, fluorescence and redox features of new vic-dioxime ligand bearing pyrene and its metal complexes


Yılmaz İ. , Kilic A., YALCINKAYA H.

CHEMICAL PAPERS, vol.62, no.4, pp.398-403, 2008 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 62 Issue: 4
  • Publication Date: 2008
  • Doi Number: 10.2478/s11696-008-0046-7
  • Title of Journal : CHEMICAL PAPERS
  • Page Numbers: pp.398-403

Abstract

A new vic-dioxime ligand, N,N'-bis(aminopyreneglyoxime) (LH(2)), and its copper(II), nickel(II) and cobalt(II) metal complexes were synthesized and characterized by elemental analyses, IR, UVVIS and (1)H and (13)C NMR spectra (for the ligand). Mononuclear complexes were synthesized by a reaction of ligand (LH(2)) and salts of Co(II), Ni(II), and Cu(II) in ethanol. The complexes have the metal-ligand ratio of 1: 2 and metals are coordinated by N,N' atoms of vicinal dioximes. The ligand acts in a polydentate fashion bending through nitrogen atoms in the presence of a base, as do most vic-dioximes. Detection of a H-bonding in the Co(II), Ni(II), and Cu(II) complexes by IR revealed the square-planar MN(4) coordination of mononuclear complexes. Fluorescent properties of the ligand and its complexes arise from pyrene units conjugated with a vic-dioxime moiety. Fluorescence emission spectra of the ligand showed a drastic decrease in its fluorescence intensity upon metal binding. The electrochemical properties of the complexes were studied by the cyclic voltammetry technique. The nickel complex displayed an irreversible oxidation process while the copper complex exhibited a quasi-reversible oxidation and reduction processes based on the copper Cu(II)/Cu(III) and Cu(II)/Cu(I) couples, respectively. (C) 2008 Institute of Chemistry, Slovak Academy of Sciences.