Acid catalyzed decarboxylation/aquation

The acid catalyzed decarboxylation/aquation was essentially biphasic [Eq. (32)]... 

The carbonato complexes undergo aquation to the corresponding aqua complexes by various paths depending on the nature of the complex. This aspect will be discussed briefly for complexes in which carbonate acts as a monodentate and bidentate ligand. The monodentate carbonato complexes of Co, Cr, Rh, and Ir, undergo acid-catalyzed decarboxylation. This can be represented by Eq. (28). 

The acid catalyzed aquation of the chelated carbonato complexes involves three steps (i) the initial rapid protonation pre-equilibrium of the exocyclic oxygen, (ii) carbonate ring opening, and (iii) decarboxylation of the resulting bicarbonate complex [see Eq. (30)]. 

Acid-catalyzed aquation of [Co(NH3)sOC02], cis-j8-[Co(edda)C03] , and [Co(nta)C03] has been reinvestigated using rapid scan spectrophotometry.Direct spectral evidence for the participation of proton-ated and ring-opened carbonato species was obtained. The spectral observations are consistent with previously suggested mechanisms for the decarboxylation of monodentate and bidentate carbonato complexes. 

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