Bromine standard reduction potentials

Thinking it Through Standard cell potentials for redox reactions can be calculated from the proper combination of half-cell standard reduction potentials. Looking at the target equation, the liquid bromine in changing to ... 

This is the type of reaction that Balard first used to isolate liquid bromine and is still the basis of the commercial preparation of the element from seawater. The above equation is certainly an oversimplification of the actual industrial process. Recall, for example, that standard reduction potentials are tabulated for 1 M solutions and gas pressures of 1 atm. The above reactions are generally conducted under considerably higher concentrations and pressures. 

Many organometallic complexes react strongly with chlorine and bromine. Their standard reduction potentials are as follows ... 

There is a clear antiperiplanar preference for the reaction (Scheme 4.2) due to the stabilization of the radical by coupling of the unpaired electron with bromine (ESR) in the first case. The weaker bond dissociation energy leads to a more favorable standard potential and a weaker intrinsic barrier. When the two conformers are present and can convert one into the other, the reduction follows a CE mechanism (Section 2.2.2), which goes through the more reducible of the two.1 2... 

---