Electrochemical Investigations of the Nickel(II)-Penicillamine System. 2. Direct Identification of Complex Species Involved in Catalytic Nickel Reduction on the Dropping Mercury Electrode

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Title:Electrochemical Investigations of the Nickel(II)-Penicillamine System. 2. Direct Identification of Complex Species Involved in Catalytic Nickel Reduction on the Dropping Mercury Electrode
Creators:
Banica, Florinel G.
Ion, Ana
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 63, 7, pp. 995-1006
Uncontrolled Keywords:Amino acids, Chelates, Polarography, Catalytic currents, Electrochemistry, Cysteine, Nickel complexes, Penicillamine

Abstract

The catalytic polarographic nickel prewave was investigated by making appropriate correlations between prewave current and complex species concentrations as calculated by means of available formation constants. It was concluded that the active species is (D-penicillaminato-<i>N</i>,<i>S</i>)nickel(II) [NiL], whereas the bis-ligand complex, [NiL<sub>2</sub>]<sup>2-</sup>, is inert and does not play any role in the electrode process. The catalytic character of the electrode process originates from the regeneration of [NiL] by the reaction of adsorbed ligand molecules with free nickel ions available in the bulk of the solution. Conversely, all the complex species in the Ni<sup>2+</sup>-cysteine system are labile. Consequently, the reaction mechanism in this case may include the dissociation of the complex [NiL<sub>2</sub>]<sup>2-</sup> as an alternative path for the generation of the active species, [NiL]. The bell-shaped form of the prewave was interpreted in terms of potential-dependent catalyst adsorption.

Title:Electrochemical Investigations of the Nickel(II)-Penicillamine System. 2. Direct Identification of Complex Species Involved in Catalytic Nickel Reduction on the Dropping Mercury Electrode
Creators:
Banica, Florinel G.
Ion, Ana
Uncontrolled Keywords:Amino acids, Chelates, Polarography, Catalytic currents, Electrochemistry, Cysteine, Nickel complexes, Penicillamine
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:63
Number:7
Page Range:pp. 995-1006
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19980995UNSPECIFIED
ID Code:1358
Item Type:Article
Deposited On:06 Feb 2009 17:08
Last Modified:06 Feb 2009 16:08

Citation

Banica, Florinel G.; Ion, Ana (1998) Electrochemical Investigations of the Nickel(II)-Penicillamine System. 2. Direct Identification of Complex Species Involved in Catalytic Nickel Reduction on the Dropping Mercury Electrode. Collection of Czechoslovak Chemical Communications, 63 (7). pp. 995-1006. ISSN 0010-0765

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