Proton transfer in transition metal complexes

The proton transfer reactions, which are extremely fast, are controlled by the area that the incoming proton attacks (regiochemistry) and by the possible migration to other parts of the molecule. They can be accompanied by further transformations. In the chemistry of the transition metal complexes, these reactions often lead to ligands dissociation or isomerizations. The first case is very common and important in the chemistry of complexes with carbon-donating ligands (organometallic).La protonation of oxyanions (which are obviously basic) leads to hydroxo compounds that often dimerize (case of CrO₄^2-) or condense polyanions (case of VO₄^3-) .