Organocobalt species

Dendrimers incorporating Co carbonyls and other organocobalt species have been the subject of a recent review.91 This sets the scene for a likely growth of interest in such systems in the future. 

Much of the foundational work concerning organocobalt species can be found elsewhere. A comprehensive examination of the Kterature up to 1994 appears in a pair of reference series [4, 5], with the former covering research up to 1982 and the latter covering work between 1982 and 1994. Each series contains a chapter on... 

Organocobalt species are of great interest to researchers, the most obvious... 

In this section, we present material dealing with the direct oxidation and reduction of a variety of organocobalt species, including complexes with more than one cobalt center, electrodes functionalized with cobalt complexes, cobalt-containing SchifF-base complexes, cobalt porphyrins and corroles, and macrocyclic tetraamines. 

Several organocobalt species have been observed to catalyze the two-electron reduction of carbon dioxide. Depending on the pathway for reduction that is followed, different products arise. If the reaction proceeds via rapid sequential uptake of two electrons, carbon monoxide is produced ... 

The preliminary developments with TINPIN and organocobalt species are very encouraging and bode well for the future development of synthetic procedures that use radical-radical coupling methods controlled either by organic or organometallic persistent radicals. 

On the other hand, five other possibilities exist (b) the rearrangement is influenced by the Co through a loose electronic influence in the radical pair (c) there is an electron transfer from the radical to Co(II) to produce Co(I) and a carbonium ion and (d) there is an electron transfer from the Co(II) to the radical to produce Co(III) and a carbanion. In cases (c) and (d), the ionic substrate derivative would rearrange (e) the Co(II) binds to the substrate radical to form a o-bonded species, and then this new organocobalt species rearranges or generates... 

It is our belief that the evidence is overwhelming that there is a conformational trigger responsible for Co—C bond homolysis. The central issue is the nature of the mechanism. Prior to assessing possible mechanisms in more detail, we first briefly review information on Co—C bond dissociation enthalpies (BDEs) for Bl2 derivatives and Bi2 models in solution and relate this information to other well-established properties of these organocobalt species. 

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