Density Functional Study of CO Insertion into the Metal-Alkyl Bond in Bis(cyclopentadienyl)-Zr-(CH3)2

The migratory insertion reaction of CO into the zirconium-alkyl bond in bis(cyclopentadienyl)-Zr-(CH3)2 has been investigated by means of density functional calculations. CO coordination processes prior to insertion have been analyzed considering both the case of "lateral" and "central" coordination, finding lateral coordination, leading to a O-outside arrangement of the ensuming acyl complex, to be thermodynamically and kinetically favored. The relative stability of the O-outside and O-inside ?2-bound acyl complexes has been investigated, finding the O-inside isomer to be the most stable by 2.9 kcal/mol, with an energy barrier for the conversion between the two acyl isomers of 12.2 kcal/mol, in excellent agreement with available experimental data. Finally, the insertion of the residual alkyl group into the acyl moiety, leading to a ?2-bound ketone, has been investigated.