Use of Hydrophobic Ligands for the Stabilization of Low-Valent Transition Metal Complexes. 1. The Effect of N-Methylation of Linear Tetraazaalkane Ligands on the Properties of Their Copper Complexes

Gilad Golub, Dan Meyerstein, Haim Cohen, Piero Paoletti, Andrea Bencini, Luigi Messori, Ivano Bertini

Research output: Contribution to journalArticlepeer-review

109 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)8353-8361
Number of pages9
JournalJournal of the American Chemical Society
Volume117
Issue number32
DOIs
StatePublished - 1995
Externally publishedYes

Fingerprint

Dive into the research topics of 'Use of Hydrophobic Ligands for the Stabilization of Low-Valent Transition Metal Complexes. 1. The Effect of N-Methylation of Linear Tetraazaalkane Ligands on the Properties of Their Copper Complexes'. Together they form a unique fingerprint.

Cite this