Cysteine Complexes with the Cobalt(III) Ion. II. Spectrophotometric Study of the Nature of Coördinationin the Complexes of Cysteine with the Cobalt(III) Ion

XAS Investigation of biorelevant cobalt complexes in aqueous media

“…8,9 MPG acts as radioprotective agent by scavenging reactive oxygen species produced by irradiation 10 and has the ability to protect against drug-induced toxicity. 11 The bis-cysteinato Co(III) complex, [Co(Cys) 2 (H 2 O) 2 ] 2À , in solution has been explored long ago by spectrophotometric studies 12,13 and the tris-cysteinato Co(III) complex, [Co(Cys) 3 ] 3À by spectrophotometric, NMR and circular dichroism studies. [12][13][14][15] For these two complexes, the cobalt coordination spheres have been reported with, respectively two and three bidentate (N,S) cysteinato ligands.…”

Cobalt Speciation Study in the Cobalt—Cysteine System by Electrospray Ionization Mass Spectrometry and Anion-Exchange Chromatography Inductively Coupled Plasma Atomic Emission Spectrometry

“…N, S coordination in [Co III L 2 ] Ϫ has been demonstrated in former studies by UV spectroscopy. 49,50 It has also been demonstrated by X-ray crystallography in the trimeric Co 51 The deprotonated carboxylate group of cysteine seemed not to coordinate cobalt for steric reasons. Ϫ (m/z 332-334 and 368-370) ( Fig.…”

“…This decrease might originate from the progressive formation of a new Co(III) complex that was supposed to be the monometallic tris cysteinate [Co III L 3 ] 3Ϫ , as stated in the literature. 50 It is well known that Co(III) occurs in an octahedral environment, 38 and particularly in [Co III L 3 ] 3Ϫ the coordination sphere of the metallic center might be filled by three cysteine ligands coordinated by (N, S). Moreover, K 3 [Co III (L-cys-N, S) 3 ]•3H 2 O had been synthesized and characterized 52 by nuclear magnetic resonance (NMR), circular dichroism (CD), and UV-Visible spectroscopy, and the ⌬-RRR diastereoisomer (which is a right-handed helix) (Scheme 3) had been demonstrated to form selectively.…”

A linear S-bridged trinuclear cobalt(III) complex with 2-aminobenzenethiol: synthesis, crystal structure, and spectroscopic characterization

“…Chelating N/S donors have been used as ligands to transition metals for the better part of a century [8] and homoleptic metal complexes of both o -aminobenzenethiolate (abt) [9] and 2-aminoethanethiolate (aet) [10], including those of the form ML 3 for both L = abt and aet, have been known since the 1950's. In addition, the ability of such ML 3 complexes to act as metalloligands to a central metal and form linear trinuclear species of the form [M′(ML 3 ) 2 ] n+ has been known since the 1960's [11, 12].…”