(BQ) Part 2 book "Electrochemical methods - Fundamentals and applications" has contents: Electrode reactions with coupled homogeneous chemical reactions, electrode reactions with coupled homogeneous chemical reactions, electrode reactions with coupled homogeneous chemical reactions, photoelectrochemistry and electrogenerated chemiluminescene, electrochemical instrumentation,.and other contents. | CHAPTER 12 ELECTRODE REACTIONS WITH COUPLED HOMOGENEOUS CHEMICAL REACTIONS CLASSIFICATION OF REACTIONS The previous chapters dealt with a number of electrochemical techniques and the responses obtained when the electroactive species (O) is converted in a heterogeneous electron-transfer reaction to the product (R). This reaction is often a simple one-electron transfer, such as an outer-sphere reaction where no chemical bonds in species О are broken and no new bonds are formed. Typical reactions of this type are Fe(CN)^" + e The equilibrium constant of () favors the hydrated form. Thus the forward reaction in () precedes the reduction of H 2 C=O, and under some conditions the current will be governed by the kinetics of this reaction (yielding a so-called kinetic current). Other examples of this case involve reduction of some weak acids and the conjugate base anions, the reduction of aldoses, and the reduction of metal complexes. (b) EC Reaction (Following Reaction) O + ne±±R RR^~ () () ., where R is an activated olefin, such as diethyl fumarate (see Figure , path 4). In this example, the reaction that follows the electron transfer is a second-order reaction, and this case is sometimes designated as an EC 2 reaction. Sometimes, yet another chemical reaction follows the first; for example, in the dimerization of olefins, there is a concluding (two-step) protonation process: R\~ + 2 H + - * R 2 H 2 () This sequence is an ECC (or EC2C) reaction. The products of one-electron transfers can also rearrange (see Figure , path 3), because a bond is weakened. For similar reasons, electron transfers can also lead to loss of ligands, substitution, or isomerization in coordination compounds. Examples include + [Cp*Re(CO) 2 (p-N 2 C 6 H 4 OMe)] + e -> [Cp*Re(CO)2(p-N2C6H4OMe)] -^ Cp*Re(CO) 2 N 2 + C 6 H 4 OMe in n Co Br 2 en 2 + 6H 2 O + e -> Co (H 2 O) 6 + 2Br~ + 2en () () 5 (where Cp* = 77 -СзМе5 and
