The Spectrochemical Properties of bis-(α-Methioninephosphonato)Copper(II) in Aqueous Solution

Abstract

The combined results of spectrophotometric measurements and e.s.r. spectra, as well as those obtained from potentiometric titration studies, are used to determine the structure of the individual complex species formed between copper(II) ion and 1-amino-3-methylthiopropane-phosphonic acid (α-MetP) in aqueous solution. The e.s.r. parameters are typical for CuN₂O₂ coordination geometries. The d-d absorption spectrum of [Cu(α-MetP)₂]^2-chromofore in aqueous solution has been treated by the Angular Overlap Model in C_2h, symmetry. Low-symmetry splittings of the broad asymmetric absorption band in the measured spectrum were found by Gaussian analysis. The effect of the σ-and π-bonding of bidentate ligand upon the central ion d-orbital energies is destribed in a ligand-field framework.

Key Words:

• angular overlap model
• electronic spectra
• copper(II) complexes
• phosphomethionine
• species in solution
• low symmetry

Notes

Abreviations: α-Ala - α-alanine, Alaha - L-α-alaninehydroxamic acid, α-AlaP - α-alanine-phosphonic acid, Glyha - glycinehydroxamic acid, Hisha - L-histidinehydroxamic acid, Leuha - L-α-leucinehydroxamic acid, L-Met - methionine, α-MetP - methioninephosphonic acid, Sarha - sarcosinehydroxamic acid