Solution equilibria and structural characterisation of the transition metal complexes of glycyl-l-cysteine disulfide

Solution behavior of Hg(II)-cystamine by Uv-Vis and199Hg NMR

“…The absence of HgÀ ÀN contacts in 1 is also in contrast to that observed in polymeric [Hg(bis(2-pyridyl)disulfide)X 2 ] (X ¼ Cl and Br), where the repeating units are held together with À ÀSSÀ À bonds with Hg 2þ attached to the N atom [24]. A similar observation is also made in the adducts of Zn 2þ , Cd 2þ and Ni 2þ with D-penicillamine disulfide, oxidized glutathione and L-cysteinylglycine disulfide, where the amino, carboxylate and amide functional groups are exclusively involved in metal binding [25,26]. The absence of HgÀ ÀN in 1 is due to the protonated amine groups.…”

Ferrocenoyl-amino acids: redox response towards di- and trivalent metal ions

“…Furthermore, in the metal complexes the amide NH stretch is absent for ligand 2a, suggesting either deprotonation or deprotonation and complexation. NH deprotonation was observed for Trp complexation of Eu 3+ and is commonly observed in peptide complexes of Cu 2+ , Ni 2+ [56][57][58][59], and Co 2+ [60][61][62][63].…”

Nickel Ion Complexes of Amino Acids and Peptides

“…The oxidation of thiols to disulfi des, however, dramatically reduces the affi nity of the sulfur atoms towards nickel(II). Although the existence of Ni-S(disulfi de) bonds has been proven in the solid state for nickel(II) complexes of several model compounds [92], similar interactions were ruled out in the nickel(II) complexes of oxidized glutathione, (CysGly) 2 and (GlyCys) 2 [93,94]. The presence of the separated (NH 2 , COO Ϫ ) or (NH 2 , CO) binding sites, however, results in the formation of [NiL] complexes as the major species and their structure is stabilized by the formation of macrochelates.…”