Copper (II) EPR in Amino Phosphonic Polyampholytes

Copper (II) interaction and ion-exchange kinetics with dimethylamine (PA-1), trimethylamine (PA-2), pyridine (PA-3), phosphonoamine (PA-4), ethylene diamine phosphonic (PA-5, PA-6, PA-7), diethylamine (PA-8) ampholytes and phosphonic acid cationite CMF were investigated. In PA-1, PA-2, PA-3, PA-4, and PA-8, ethylene diamine phosphonic ampholytes (PA-5, PA-6, PA-7) and phosphonic acid cationite CMF Cu(R-HPO₃)₂(H₂O)₄ (A) and aqua complexes [Cu (H₂O)₆]²⁺are forming. The ampholyte polymer matrix structure consists of two packaging density segments. In the first place copper, (II) occupy high density region with a low water content where complex structure is Cu(R-HPO₃)₂(H₂O)₄. The self-diffusion coefficient of Cu²⁺ calculated on the basis of EPR spectra analysis is in agreement with self-diffusion coefficient measured by radioactive-tracer technique. In ethylene diamine phosphonic polyampholytes PA-5, PA-6, PA-7 copper (II) forms stable complexes with amino group nitrogen atoms containing 4 (D) or 2 nitrogen atoms (E). In PA-5, PA-7 complexes with 2 and 4 nitrogen atoms and Cu(R-HPO₃)₂(H₂O)₄ are formed. In PA-6, isotropic line F appeared, which belongs to E complexes where Cu²⁺ is exchange coupled to each other. In PA-7, EPR spectra consist of line A, line E and isotropic line G of copper (II) aqua complexes. Such multiversity of copper (II) complexes is due to these polyampholytes’ chemical inhomogeneity. Copper (II) sorption and desorption kinetics depending on outer aqueous solution concentration (CuSO₄ or HCl) and ampholyte grain diameters were investigated. Desorption kinetic curves are approximated by external diffusion and diffusion with moving boundary mechanisms.