Infrared Spectra of Complexes of L-Cysteine and Related Compounds with Zinc(II), Cadmium(II), Mercury(II), and Lead(II)¹

Ultrasensitive colorimetric detection of Cu2+ ion based on catalytic oxidation of l-cysteine

“…3b, the sensor responded specifically toward Cu 2 þ ion without interference of other metal ions. Even though there is the fact that Lcysteine can form a chelate ring (usually 1:1) with divalent metal ions of Cd 2 þ , Pb 2 þ , Zn 2 þ and Hg 2 þ (Shindo and Brown, 1965), nevertheless, the concentrations of metal ions used in this work were much lower than the concentration of L-cysteine, and thus the presence of such heavy metals could not disturb the Cu 2 þ ion detection process. Moreover, L-cysteine can also be oxidized in the presence of Fe 3 þ ion in some study cases (Ehrenberg et al, 1989), but the solubility product constant (Ksp) of Fe(OH) 3 is 2.79 Â 10 À 39 , and therefore, [Fe 3 þ ] is only 7 Â 10 À 19 M under pH 6.8, which could not have obvious interferences with the reaction (Liu and Millero, 2002).…”

The crystal and molecular structure of dichloro(S-methyl-L-cysteine)palladium(II) monohydrate

“…There are several preparative and spectro-scopic studies concerning metal complexes of sulphurcontaining amino-acids (e.g. Li & Manning, 1955;Lenz & Martell, 1964;Shindo & Brown, 1965;McAuliffe, Quagliano & Vallarino, 1966;Livingstone & Nolan, 1968) which show that these ligands can play different roles in the different cases as they have three points for coordination to metal. In the present report the results of the structure analysis of dichloro-(Smethyl-L-cysteine)palladium(I I) monohydrate are given, which show that S-methyl-L-cysteine behaves as a bidentate ligand coordinating through sulphur and nitrogen to palladium.…”

pH-Controlled Hydrothermal Synthesis of Submicrometer-Sized CdS Spheres with Uniform Size Distribution

“…While there are several suggested complex formation mechanisms, the commonly accepted ones are those involving the formation of a polymeric chain and 3:4 complexes (Cd n (L-Cys) n and Cd3(L-Cys)4). [15][16][17] The similarity between the two complex models is that they both indicate the formation of Cd-S and Cd-O bonds but not the coordination of the ammonium group in L-cysteine with the Cd(II) ion. 15,16 The possible reason for the marked difference between the morphologies of the CdS particles synthesized at pH 3, 7, and 12 is the ammonium-amine conversion when the solution pH is increased to 12, which is approximately 2 pH units higher than the pK a value of the ammonium group (α-NH 3 + ) in L-cysteine (pK a of α-NH 3 + = 10.28).…”

“…It is already known that Cd(II)-L-cysteine complexes in an aqueous solution indicate the formation of Cd-S and Cd-O bonds but not the coordination of the ammonium group in L-cysteine with the Cd(II) ion. 15,16 By controlling the deprotonation of ammonium group of Cd(II)-L-cysteine complex, one can easily control the intermolecular interactions between the complexes. Qian and coworkers successfully synthesized three-dimensional (3D) and one-dimensional (1D) CdS nanostructures by carrying out reactions between Cd(II) and L-cysteine in a binary solution comprising ethylenediamine and water.…”