Wydział Chemii

Barbara Kurzak

D. Kroczewska

Julia Jezierska

1998

Polyhedron

17

1831-1841

10.1016/S0277-5387(97)00528-7

Naukowa

Angielski

Artykuł

Stabilities of the mixed-ligand complexes of Cu²⁺ ion with diethylenetriamine [bis(2-aminoethyl) amine, dien)] as a primary ligand and α-alaninehydroxamic acid [2-amino-N-hydroxypropanamid, α-Alaha] or β-alaninehydroxamic acid [3-amino-N-hydroxypropanamid, β-Alaha] as a secondary ligand L and their absorption and EPR spectra at various pH values are reported. The visible spectra exhibit a characteristic red shift and a shoulder at lower energies indicating a five-coordinate structure of the formed complexes. The change of the EPR spectral parameters as a function of pH reflects two modes of an equatorial-axial chelation by aminohydroxamic acid ligand L in [Cu(dien)(HL)]²⁺ and [Cu(dien)(L)]⁺ species, while the diethylenetriamine nitrogens are coordinated at three equatorial positions in each case. α-Alaha is a more effective chelating ligand than β-Alaha in the Cu²⁺-dien-L ternary system. This is reflected in the much higher basicity-adjusted stability constants, logK_{Cudien)(α-Alaha)(β-Alaha)} ∑pK^H.

copper(II) complexes, mixed-ligands complexes, five-coordinate, aminohydroxamic acids, diethylenetriamine, e.s.r. spectra, vis spectra

https://doi.org/10.1016/S0277-5387(97)00528-7

http://www.elsevier.com