Study and Classification of Reactions

Mechanistic studies are of great importance in homogeneous catalysis. The active catalyst, often prepared in situ, is not easily isolated and, even when it is, can prove misleading (17). The comprehension of the catalytic process is therefore not an easy matter. In addition to producing kinetic measurements, 

Each reaction type (oxidative addition, reductive elimination, etc.) was studied according to the electronic configuration (at this time only the even dn configurations have been considered), the coordination number, and the coordination geometry. The matrices that we have composed for the evaluation (Matrices 1, 2, 3, 4, 5, 6, and 7 see also Section I,C), show the structure d -ML for which the reaction is allowed or forbidden. We must note that, in most of the cases, the rules that we present derivefrom theoretical studies found in the literature and that exceptions certainly exist. Another difficulty in this reaction evaluation is the importance of the coordination geometry (15b), related to the spin state (low or high), the choice of which is particularly difficult. 

Reaction name General descriptiona Example AOS, ANVE, ACN, A Qb Ref. 

6 AOS = variation of the oxidation state of the metal, ANEV = variation of the number of valence electrons, ACN = variation of coordination number, AQ = variation of the global charge. c Two different representations of the same reaction. d This is not a reaction but a canonical representation. 

Reactions 1 through 8 of Table II represent different types of mononuclear two-electron equivalent oxidative additions. A first condition for the feasibility of these reactions is the presence of a vacant coordination site in the complex. Matrix 1 shows the structures for which the oxidative addition is possible. 

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