CH3, C(CH3)3): Evidence for a Dissociative Mechanism and Estimation of the Re−(η2-Arene) Bond Strength Kinetic and Mechanistic Study of the Displacement of η2-Coordinated Arenes from Cp*Re(CO)2(η2-C6H5R) (R = H

The displacement of the arene molecule from Cp*Re(CO)2(η2-arene) (arene = benzene, toluene, tert-butylbenzene) by pyridine in heptane solution is studied. The rate constants for arene dissociation from the Re center are found to vary in the order Cp*(CO)2Re-(η2-toluene) < Cp*(CO)2Re-(η2-benzene) ≈ Cp*(CO)2Re-(η2-tert-butylbenzene) and are a function of the steric and electronic properties of the arene substituents. Activation parameters yield a lower limit of 19-21 kcal/mol for the Cp*(CO)2Re-(η2-arene) bond strength.

Kinetic and Mechanistic Study of the Displacement of η2-Coordinated Arenes from Cp*Re(CO)2(η2-C6H5R) (R = H, CH3, C(CH3)3): Evidence for a Dissociative Mechanism and Estimation of the Re−(η2-Arene) Bond Strength Academic Article