Cobalt complexes, acetylacetone, electron

In the above examples, the nucleophilic role of the metal complex only comes after the formation of a suitable complex as a consequence of the electron-withdrawing effect of the metal. Perhaps the most impressive series of examples of nucleophilic behaviour of complexes is demonstrated by the p-diketone metal complexes. Such complexes undergo many reactions typical of the electrophilic substitution reactions of aromatic compounds. As a result of the lability of these complexes towards acids, care is required when selecting reaction conditions. Despite this restriction, a wide variety of reactions has been shown to occur with numerous p-diketone complexes, especially of chromium(III), cobalt(III) and rhodium(III), but also in certain cases with complexes of beryllium(II), copper(II), iron(III), aluminum(III) and europium(III). Most work has been carried out by Collman and his coworkers and the results have been reviewed.4-29 A brief summary of results is relevant here and the essential reaction is shown in equation (13). It has been clearly demonstrated that reaction does not involve any dissociation, by bromination of the chromium(III) complex in the presence of radioactive acetylacetone. Furthermore, reactions of optically active... 

A linear dependence of log on log rf was found [175] in the case of a one-electron reduction of cobalt(III) complexes with acetylacetone (AcAc) in several aprotic solvents, but the behavior in protolytic solvents was different. 

A novel all-cobalt nonaqueous RFB has recently been studied [42]. Other than previously mentioned ligands, that is, the acetylacetonate complexes and the 2,2-bipyridine complexes, a third type of ligand complex, bis(acetylacetone) ethyle-nediamine complex, was reported. The cell potential for one-electron disproportion is 2.0 V, and the coulombic efficiency is over 90%. 

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