Wydział Chemii

Barbara Kurzak

Anna Kamecka

K. Kurzak

Julia Jezierska

Paweł Kafarski

1998

Polyhedron

17

4403-4413

10.1016/S0277-5387(98)00243-5

Naukowa

Angielski

Artykuł

The stoichiometries and stability constants of the copper(II) complexes with seven aminodiphosphonates [R–N(CH₂PO₃H₂)₂, L] containing iminomethylenephosphonate moieties have been determined pH-metrically at 25°C and at an ionic strength of 0.20 mol dm⁻³ (KCl). The results suggest for L=1–6 only equimolar species: [Cu(H₂L), [Cu(HL), [CuL] and two hydroxo [CuH₋₁L] and [CuH₋₂L], in the pH range of 2–11.5, the only difference is the presence of an additional [Cu(H₃L)] species (∼15%) at low pH for N-3-picolyliminodi(methylenephosphonic) acid. For L=7 the model contains protonated and non-protonated 1:2 species. From the comparative analysis of the stability and the spectroscopic (UV–VIS and EPR) data it has been established that the ligands in [CuHL] and [CuL] are tridentate; the formation of two five-membered chelate rings leads to very stable complexes. The LMCT bands from O⁻ (PO₃²⁻) and N_imino to Cu² are at 225–231 and 302–277 nm.

potentiometry, stability constants, copper(II)complexes, aminopolyphosphonates, EPR spectra, UV–VIS spectra

https://doi.org/10.1016/S0277-5387(98)00243-5

http://www.elsevier.com