Title
Speciation and structure of copper(II) complexes with (S)-phenylalanine- and (S)-tryptophanhydroxamic acids in methanol/water solution: a combined potentiometric, spectrophotometric, CD and ESI-MS study
Author
Francesco Dallavalle, Matteo Tegoni
Year
2001
Journal
Polyhedron
Abstract
Complexation equilibria of (S)-phenylalaninehydroxamic and (S)-tryptophanhydroxamic acids (HL) with copper(II) were studied in methanol/water solution in order to avoid the precipitation of a polynuclear species observed in aqueous solution. Among the different techniques used (potentiometry, absorption spectrophotometry, spectropolarimetry and ESI-MS), mass spectrometry data allowed to detect a pentanuclear species [Cu5L4H−4]2+ instead of the dinuclear one, [Cu2L2H−1]+, usually reported for the α-aminohydroxamates in aqueous solution. A cup structure of the pentanuclear cation is proposed, which is similar to that determined by X-ray analysis for the corresponding species of β-alaninehydroxamic acid.
Instrument
J-715
Keywords
Circular dichroism, Coordination chemistry, Ligand binding, Biochemistry