Solid-state spectroelectrochemistry of crosslinked donor bound polymer films

Abstract

A new electroactive material has been prepared by attaching the potassium salt of 1,3-di(/>-methoxyphenyl)-5-(/?hydroxyphenyl)-A2-pyrazoline to cross-linked chloromethylated polystyrene resins. The polymer Can be readily coated from benzene suspensions onto metallic electrodes. At these modified electrodes, electrochemical charge transfer reactions are accompanied by large optical changes as pyrazoline cations are formed through the film bulk. Studies of the electrochemical and optical changes as a function of sweep rate and time indicate that electrons are transferred between monomeric pyrazoline species, and that the polymer matrix is characterized by a considerable degree of donor site flexibility.

Cyclic voltammetry of biofilms of wild type and mutant Geobacter sulfurreducens on fuel cell anodes indicates possible roles of OmcB, OmcZ, type IV pili, and protons in extracellular electron transfer

“…By analogy to Heller's electrode immobilized enzymes, homogeneous electron transfer from individual microbes comprising the biofilm may be driven thermodynamically by a concentration gradient of reduced mediator in which reduced mediator is generated by the microbes and consumed by the anode. 70,71 Our analysis also indicates that the magnitude of catalytic current is limited by rate of acetate uptake by the microbes. Furthermore, the homogeneous electron transfer process (step 3), when accelerated during fast scan CV, becomes limited by diffusion of protons in the biofilm generated by oxidation of acetate (step 1), which serve as charge compensating counter ions in the homogenous ET.…”

Modified Electrodes

“…Consequently, charge transfer by successive exchanges of electrons between neighboring redox sites, as shown in Scheme 4, was proposed by Kaufman and Engler. 159 A flow of counterions is necessary to compensate the redox charge change, and there will be polymer lattice motion to accommodate the counterion and solvent flow, and the motions of neighboring sites toward one another. The overall process is actually very complex.…”

Sulfite Oxidation Mediated by Ortho-Phenylenediamine / Co(ii)-Tetrakis(para-Aminophenyl)porphyrin Copolymers in Acid Medium

“…Electrochemical techniques such as in situ FTIR spectroscopy [14][15][16], Raman resonance spectroscopy [17], and other methods, have been used to study the electropolymerization mechanism, to characterize the polymer film and to discover different applications of polyOPD [18]. Also, it is possible to polymerize porphyrins of different transition metals [19][20][21], one of them being Co(II)-tetrakis(para-aminophenyl)porphyrin [22][23][24][25][26][27][28][29] on different electrodic surfaces. This polymer shows electrocatalytic activity on several interesting redox reactions [22][23][24][25][26][27][28][29] such as sulfite oxidation.…”

“…Also, it is possible to polymerize porphyrins of different transition metals [19][20][21], one of them being Co(II)-tetrakis(para-aminophenyl)porphyrin [22][23][24][25][26][27][28][29] on different electrodic surfaces. This polymer shows electrocatalytic activity on several interesting redox reactions [22][23][24][25][26][27][28][29] such as sulfite oxidation. However films are fragile, unstable and very thin [30].…”