Solid-state and solution characterizations of [(TMPA)Cu(II)(SO3)] and [(TMPA)Cu(II)(S2O3)] complexes: Application to sulfite and thiosulfate fast detection

J Inorg Biochem. 2021 Dec:225:111601. doi: 10.1016/j.jinorgbio.2021.111601. Epub 2021 Sep 22.

Abstract

Sulfite (SO32-) and thiosulfate (S2O32-) ions are used as food preservative and antichlor agent respectively. To detect low levels of such anions we used Cu(II) complex of the Tris-Methyl Pyridine Amine (TMPA) ligand, denoted L. Formation of [LCu(SO3)] (1) and [LCu(S2O3)] (2) in solution were monitored using UV-Vis, EPR and cyclic voltammetry, while the solid-state X-ray structures of both complexes were solved. In addition, we also evaluated the pH range in which the complexes are stable, and the anions binding affinity values for the [LCu(solvent)]2+ (3) parent complex. As a matter of illustration, we determined the sulfite content in a commercial crystal sugar.

Keywords: Copper(II); EPR; Sulfite; TMPA; Thiosulfate; UV–Vis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chelating Agents / chemical synthesis
  • Chelating Agents / chemistry*
  • Colorimetry
  • Coordination Complexes / chemical synthesis
  • Coordination Complexes / chemistry*
  • Copper / chemistry
  • Food Contamination / analysis
  • Sulfites / analysis*
  • Sulfites / chemistry
  • Thiosulfates / analysis*
  • Thiosulfates / chemistry

Substances

  • Chelating Agents
  • Coordination Complexes
  • Sulfites
  • Thiosulfates
  • Copper