Solution studies of some new oxamides - co-ordination behaviour towards Cu(II) ions
Agnieszka Dobosz1, Jan Spychała, Henryk Kozłowski
1Department of Basic Medical Sciences, Wroclaw Medical University, Kochanowskiego 14, 51-601Wrocław, Poland. adob@basmed.am.wroc.pl
Abstract:
The co-ordination chemistry of some new oxamides towards Cu(II) ions was studied using various techniques: potentiometry, voltammetry, spectroscopy (UV-Vis, CD and EPR) and ESI-MS spectrometry. All tested compounds chelate the copper(II) ions with formation of 1:1 and 1:2 (metal-to-ligand ratio) complexes. The Cu(II) ions are bound by 1N, 2N or 3N nitrogen donor systems. Additionally, an unusual co-ordination to amide N-atoms without additional anchoring site is suggested. The (14)N hyperfine splitting observed for the system ox6-Cu(II) above pH 10 clearly indicates the involvement of at least three N donor atoms in the copper ion binding. Moreover, the surrounding by three amide-N and one carbonyl-O stabilizes the high oxidation state of copper(III), although such complexes are very unstable in solution.
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