Ligand-deficient catalysis

This is a case of competitive inhibition, as the inhibitor and reactant compete directly for the active site. Ligand-deficient catalysis is then a special case of competitive inhibition when the ligand itself acts as an inhibition although it is a necessary ingredient of the catalyst system. 

Analogously to the treatment of ligand deficient catalysis we introduce the concentration of C>u into the total catalyst balance and by defining Cx through Dj, the reaction rate is... 

Comparison between (5.109) and (5.102) reveals, that in (5.109) Di should be replaced by Dj and equilibrium adsorption of inhibition in case of ligand-deficient catalysis was defined in a slightly different way. 

Ligand-deficient catalysis, inhibition, and corresponding kinetic models were considered in Section 5.4.2. Generation of active sites in catalysis by organometaUic complexes involves a step outside the catalytic cycle, namely the loss of the figand from the catalyst. This step frees the coordinative site, allowing binding of the reactants. 

Detailed kinetic studies are essential to help establish that a multicenter complex is not dissociating to an active monomeric catalyst—as is usually the case (/, p. 405). An added problem in some of these ligand-deficient systems (394. 405) is to establish that the catalysis is homogeneous. Even when an active polynuclear system is confirmed, it is likely impossible to demonstrate unequivocally that reactivity does not occur at a single... 

In many reactions of homogeneous catalysis, one or several linear pathways are connected to the actual catalytic cycle. The most common example is catalysis by a ligand-deficient complex, initiated by reversible ligand loss. Also in this category are certain types of inhibition, activation, and poisoning. 

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