Skip to Content
Merck
  • Fine tuning of copper(II)-chlorophyll interactions in organic media. Metalation versus oxidation of the macrocycle.

Fine tuning of copper(II)-chlorophyll interactions in organic media. Metalation versus oxidation of the macrocycle.

Dalton transactions (Cambridge, England : 2003) (2015-02-28)
Łukasz Orzeł, Bartłomiej Szmyd, Dorota Rutkowska-Żbik, Leszek Fiedor, Rudi van Eldik, Grażyna Stochel
ABSTRACT

The nature of chlorophyll interactions with copper(II) ions varies considerably in organic solvents, depending on the dominant coordinative form. Besides formation of the metallo tetrapyrrolic complex, Cu(II) ions can cause oxidation of the pigment, reversible or irreversible, which can lead to the destruction of the macrocyclic structure. All these reaction types can be distinguished within a quite narrow range of reaction conditions. The ability to form new metallo derivatives in either metalation or transmetalation reactions is obviously limited by the concentration of the potential oxidant, but can be secured below this level via suitable composition of the reaction system. The decisive factor in the selection of a specific reaction pathway is the presence of a potential ligand that can affect the reactivity of Cu(II) for example by shifting its redox potential. Spectroscopic and electrochemical studies were performed in order to determine the predominant species of Cu(II) in methanol, nitromethane and acetonitrile in the presence of chloride and acetate ions, as well as to assign their appropriate oxidizing ability. This allowed us to estimate the boundary conditions for the electron transfer processes in chlorophyll-Cu(II) systems. Chlorophyll and its free base can undergo both types of electron transfer processes, however, they reveal different susceptibilities that make this class of ligands quite versatile markers in tuning the reactivity of metal ions in solutions.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Methanol, suitable for HPLC
Sigma-Aldrich
Methanol, JIS special grade, ≥99.8%
Sigma-Aldrich
Methanol, NMR reference standard
Sigma-Aldrich
Methanol, HPLC Plus, ≥99.9%, poly-coated bottles
Sigma-Aldrich
Methanol, SAJ first grade, ≥99.5%
Sigma-Aldrich
Methanol, JIS 300, ≥99.8%, for residue analysis
Supelco
Methanol, analytical standard
Supelco
Tetrabutylammonium acetate, for electrochemical analysis, ≥99.0%
Sigma-Aldrich
Methanol, anhydrous, 99.8%
Sigma-Aldrich
Methanol, suitable for HPLC, gradient grade, 99.93%
Sigma-Aldrich
Tetrabutylammonium acetate, 97%
Sigma-Aldrich
Tetrabutylammonium acetate, technical, ≥90% (T)
Sigma-Aldrich
Methanol, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.8% (GC)
Sigma-Aldrich
Methanol, SAJ special grade
Sigma-Aldrich
Copper(II) acetate hydrate, 98%
Sigma-Aldrich
Methanol, puriss., meets analytical specification of Ph Eur, ≥99.7% (GC)
Sigma-Aldrich
Methanol, ACS reagent, ≥99.8%
Sigma-Aldrich
Methanol, Absolute - Acetone free
Sigma-Aldrich
Methanol, ACS spectrophotometric grade, ≥99.9%
Sigma-Aldrich
Methanol, Laboratory Reagent, ≥99.6%
Sigma-Aldrich
Methanol, ACS reagent, ≥99.8%
Sigma-Aldrich
Methanol, ACS reagent, ≥99.8%
Supelco
Methanol, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Methanol, HPLC Plus, ≥99.9%
Sigma-Aldrich
Methanol, BioReagent, ≥99.93%
Sigma-Aldrich
Methanol, suitable for HPLC, gradient grade, ≥99.9%
Sigma-Aldrich
Methanol, suitable for HPLC, gradient grade, suitable as ACS-grade LC reagent, ≥99.9%
Sigma-Aldrich
Methanol, suitable for HPLC, ≥99.9%
Sigma-Aldrich
Methanol-12C, 99.95 atom % 12C
Supelco
Methanol solution, contains 0.10 % (v/v) formic acid, UHPLC, suitable for mass spectrometry (MS), ≥99.5%