Dihydride Formation by Oxidative Addition of

Equation (3) is reversible, argon readily repelling hydrogen to recover the original Ir(I) complex. The reverse reaction causes a decrease in both the oxidation number and coordination number of the metal, and is called reductive elimination. The equilibrium constant of Eq. (3) is reported to be X = 1.5 x 10 dm mol in benzene at 30°C. 

The product of Eq. (3) is considered to have an octahedral structure with the cts-(H)2-tranj-(P)2 arrangement based on IR and NMR data crystals suitable for X-ray analysis have not been obtained. Therefore, a triangular (side-on) transition state as depicted below is proposed for Eq. (3) 2,93 

---