Theoretical Study of the Reactivity of (π-Allyl)molybdenum Complexes

Abstract

The reactivity of allyl carbons in (π-allyl)molybdenum complexes has been investigated theoretically. The central carbon of the allyl moiety has been shown to be more reactive than the terminal carbons toward nucleophiles in Cp2Mo(η3-allyl)+ by locating a reactant complex, transition states, and products with the density functional theoretical calculations. Orbital interactions have been analyzed then by applying a paired interacting orbital scheme to the MO wave function. The local electron-accepting ability of allyl carbons has been evaluated, showing that the acidic hardness of reaction sites is a key to understand the higher reactivity of the central carbon. The regioselectivity observed in nucleophilic attacks to CpMo(η3-allyl)(CO)(NO)+ and some other (π-allyl)molybdenum complexes has also been investigated in terms of the local electron-accepting ability of the reaction sites. The terminal carbons are shown to be more reactive in these cases.