The electrochemical reduction of the Cu(II) complexes with the ligands 2,5,8,11-tetramethyl-2,5,8,11-tetraazadodecane, 2,5,9,12-tetramethyl-2,5,9,12-tetraazatridecane, and 2,6,9,13-tetramethyl-2,6,9,13-tetraazatetradecane in deaerated aqueous solutions yields the corresponding thermodynamically stable copper(I) complexes. The same complexes are obtained also via the comproportionation reaction of CuLi 2+ and Cu0 in the presence of excess ligand. ΔS0 values of the reduction processes were determined. The basicity constants of Li and the stability constants of their Cu(II) complexes were determined potentiometrically. The ESR spectra of CuLi 2+ point out that these complexes are not significantly tetrahedrally distorted. The binding constants of axial singly charged anions to the CuLi 2+ complexes were determined. Analysis of the data points out that the thermodynamic stabilization of the monovalent copper complexes via N-methylation is mainly due to the destabilization of the CuLi 2+ complexes. It is concluded that a major factor contributing to the observed effects is the hydrophobic nature of the tertiary-amine ligands.
ASJC Scopus subject areas
- Chemistry (all)
- Colloid and Surface Chemistry