Kinetics and Mechanism of Carbon Monoxide Insertion

RPt(CO)LX 93), and RIr(CO)2LX2 92) [M(CO)R] with various nucleophiles (L ) to give the corresponding M(COR)L. In addition, kinetic data have been reported for reactions of Rh(CO)2LX 233) and Rh(CO)L2X 88) [M(CO)] with RX which proceed in two steps—oxidative addition and CO insertion—to afford M(COR)X.  

By applying the steady-state approximation for the concentration of the intermediate one obtains  

Since most insertion reactions go to virtual completion, k [ and k 2 may be ignored, simplifying Eq. (21) to 

The two terms in Eq. (22) pertain to what shall be called the A, path and the 2 path, respectively. Further simplification of the rate equation is possible by one or more of the following considerations  

An invariance of to changes in the ligand L lends further support to this scheme. 

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