Ligand reaction with surface hydroxyl group

During typical surface complex formation, or ligand exchange, the surface hydroxyl group on the hydrous oxide exchanges with a similar Lewis base electron pair donor in the solution. Adsorption of either protons or hydroxide ions is interpreted in terms of an acid-base reaction at the oxide surface, i.e., the surface hydroxyl group is either protonated or deprotonated. The adsorption of ligands (anions and weak acids) on a metal-oxide surface can also be compared with complex formation reactions in solution, e.g. ... 

Alkyl ligands react easily with surface -OH groups. When only alkyl groups are present, the stoichiometry of the reaction depends on the hydroxylation degree of the surface [1]. The same is true for any polyalkyl complex, no matter the identity of the other ligands (see below). 

As with metal cations, anion chemisorption occurs on soil minerals that possess surface hydroxyl groups. The most important minerals in this regard are noncrystalline aluminosilicates (allophanes) oxides and hydroxides of Fe, Al, and Mn and layer silicate clays (edge sites only). It is the H2O or valence-unsatisfied OH ligands bound to surface metal ions (usually Fe, Al, or Mn) that are the sites of chemisorption. In general terms, the surface reaction can be written... 

The surface reaction of Ru3(CO)i2 with alumina is complex and depends on the temperature of support pretreatment. With partially hydroxylated alumina, an interaction between the CO ligands and the hydroxyl groups, via an oxidative addition, occurs with release of CO [91, 95, 99, 104] ... 

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