Macro-inorganics. Part 3. Chelation of copper(II) ion with some polymers having a poly(amido-amine) structure and their non-macromolecular models

Abstract

Copper(II) complex formation with some poly(amido-amines) and their non-macromolecular models has been studied by potentiometric and spectrophotometric (electronic and e.s.r.) techniques. Real stability constants could be determined for the macromolecular ligands. The presence of complexes such as [CuL]²⁺, [Cu(OH)L]⁺, and [Cu(OH)₂L](where in the case of polymeric ligands L represents the repeating unit) could be ascertained in aqueous solution. The stability constants of the [CuL]²⁺ complexes with macromolecular ligands are slightly lower than those of their non-macromolecular models. Some of the complexes have been obtained and studied in the solid state. They have clear-cut stoicheiometries and their electronic spectra are identical to those obtained in solution. In order to elucidate the mechanism of complex formation, low-molecular-weight models of the polymers have also been studied. The complexes of the polymers and their corresponding models show identical electronic and e.s.r. spectra.