The rate and extent of reaction between H2OFe(CN)53- and poly(2-vinylpyrazine) (PVPz) In homogeneous aqueous solutions have been measured and compared with those for the reaction between the corresponding monomeric species H2OFe(CN)53- and pyrazine). The significant differences observed are attributed to the increasingly negative charge that accumulates on the polymer-metal complex as the reaction proceeds. Solutions of PVPz(Fe(CN)53-)n exhibit almost no electrochemical responses In 0.1 M supporting electrolytes but In 1 M solutions a clear response Is evident. Stable electroactive coatings of PVPz(Fe(CN)93-)n on electrode surfaces can be prepared by exposing cross-linked deposits of PVPz to aqueous solutions of H2OFe(CN)53-. The apparent formal potentials of the redox groups in such coatings vary with the concentration of the supporting electrolyte in the way expected for cation permselective membranes. With homogeneous solutions of PVPz about 30 % of the pyrazfne groups could be coordinated to -Fe(CN)53- anions but the maximum extent of binding of -Fe(CN)53- to cross-linked coatings of PVPz was only about half as large. © 1989, American Chemical Society. All rights reserved.
Poly(2-vinylpyrazine) as a soluble polymeric ligand and as an electrode coating. reactions with pentacyanoferrate(II)
UGO, Paolo;
1989-01-01
Abstract
The rate and extent of reaction between H2OFe(CN)53- and poly(2-vinylpyrazine) (PVPz) In homogeneous aqueous solutions have been measured and compared with those for the reaction between the corresponding monomeric species H2OFe(CN)53- and pyrazine). The significant differences observed are attributed to the increasingly negative charge that accumulates on the polymer-metal complex as the reaction proceeds. Solutions of PVPz(Fe(CN)53-)n exhibit almost no electrochemical responses In 0.1 M supporting electrolytes but In 1 M solutions a clear response Is evident. Stable electroactive coatings of PVPz(Fe(CN)93-)n on electrode surfaces can be prepared by exposing cross-linked deposits of PVPz to aqueous solutions of H2OFe(CN)53-. The apparent formal potentials of the redox groups in such coatings vary with the concentration of the supporting electrolyte in the way expected for cation permselective membranes. With homogeneous solutions of PVPz about 30 % of the pyrazfne groups could be coordinated to -Fe(CN)53- anions but the maximum extent of binding of -Fe(CN)53- to cross-linked coatings of PVPz was only about half as large. © 1989, American Chemical Society. All rights reserved.
I documenti in ARCA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
