Ligand field effects, and reaction

In the lanthanide and actinide series, arguments like these are greatly eased by the very small ligand field effects. Consider the reaction... 

One strong indication of the importance of ligand field effects is the fact that substitution reactions in octahedral complexes of Pt4+, Rh3+, and Ru3+ occur without rearrangement. The following are examples of reactions of this type ... 

It would thus be expected that ligand field effects would be important in determining reaction rates and this is found to be the case. 

The ligand field stabilization energy is only one aspect of the formation of a transition state. Because the reactions are carried out in solutions, solvation of the transition state and the entering ligand may have enough effect to assist in the formation of a particular transition state. Also, the fact that some... 

Labile species are usually main group metal ions with the exception of Cr2+ and Cu2+, whose lability can be ascribed to Jahn-Teller effects. Transition metals of classes II and III are species with small ligand field stabilization energies, whereas the inert species have high ligand field stabilization energies (LFSE). Examples include Cr3+ (3d3) and Co3+ (3d6). Jahn-Teller effects and LFSE are discussed in Section 1.6. Table 1.9 reports rate constant values for some aqueous solvent exchange reactions.8... 

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