Stability, spectra and structure of the copper(II) chloride complexes in acetic acid.
Résumé
The stability constants and the electronic spectra of four molecular chlorocomplexes formed in acetic acid solutions have been calculated. The spectrophotometric measurements were performed at wavelengths ranging from 260 to 500nm and, in the near IR from 600 to 1400nm. The matrix rank treatment of more than 1000 spectrophotometric data demonstrates a minimum of five absorbing species: the solvated copper (II) acetate and four chlorocomplexes. The overall stability constants of Cu (OAc)Cl, CuCl2, LiCuCl3 and LiCuCl4 are respectively: log β1 = 3.38; log β2 = 5.57; log β 3 = 7.36; log β4 = 7.83. The structure of the monochlorocuprate with the Cu-OAc bonding in the primary coordination sphere is supported by near-IR evidence. The bathochromic shift of the absorption maxima of the d-d transition bands indicates structural changes of the complexes with a square planar configuration for Cu (OAc)Cl promoted to a flattened tetrahedron for Li2CuCl4.
Domaines
Chimie
Origine : Accord explicite pour ce dépôt