Reactions and Equilibria Not Involving Cleavage of the Co—C Bond

Several organo-ligands can gain or lose a proton. The values of pK given in the accompanying tabulation have been reported for complexes of the type [RCq(DMG)2X] 163). 

Values of p/Tb have been determined for protonation of the pyridiomethyl ligand in all three isomers of the complexes 

Acid and base can, of course, induce many reactions of organocobalt(III) complexes (see Section B below, and Section VI,B, C, D), presumably through the formation of reactive intermediates by the gain or loss of a proton, e.g.. 

Organo-ligands which can pick up a proton should also be able to act as Lewis bases towards metal ions, but only two cases have so far been reported. Ethinyl- and vinylcobalamin both show reversible equilibria with Ag(I) ions, which have been ascribed to equilibria such as 

NMR studies show no exchange of protons between solvent and organo-ligands [see, for example, ref. (161)]. 

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