Search

The theoretical treatment of single electron transfer (SET) of the redox chemistry mediated by f-element complexes is reviewed and summarized. The different computational strategies to account for the SET energy are presented and commented on the basis of the subsequent mechanistic investigation. Moreover, the mechanistic investigation of the subsequent reactivity, mainly in the field of heteroallene activation, using DFT-based approaches is also summarized. All reported reactivities are found to involve formation of bimetallic species and share in common the formation of the same key intermediate in which the substrate is doubly reduced and stabilized by two oxidized metal centers. Modern computational methods are found to efficiently account for such reactivity. [ABSTRACT FROM AUTHOR]

The orthoC–H bond activation of several pyridine and pyridine N-oxide derivatives mediated by Cp2An(iv)(CH3)2and Cp2An(iii)(CH3) (Cp = C5H5and An = U, Np, Pu) have been investigated at the DFT level. For uranium(iv) complex, an excellent agreement with experimental observations is found, and particularly in the case of 2-picoline where only orthosp2C–H activation is observed without any sp3C–H activation. These differences of reactivity can be explained by the charges distribution at the metathesis transition state level. A predictive study of the reactivity of neptunium and plutonium complexes with pyridine and pyridine N-oxide is reported. This study shows that neptunium and plutonium have almost the same reactivity. The C–H activation mediated by actinide (iii) complexes have found to be more kinetically and thermodynamically favorable than for actinide (iv) complexes. The influence of 5f electrons on organoactinide reactivity is found to be small by comparing implicit and explicit treatment of 5f electrons. [ABSTRACT FROM AUTHOR]

Abstract: A predictive reactivity of Cp2An(IV)Me2 (with An=uranium [U], neptunium [Np] and plutonium [Pu]) with pyridine N-oxide has been studied at the theoretical level. The predictive reaction, which consists in the formation of a formaldehyde complex, begins after the initial formation of a cyclometalated complex produced by a C-H activation of the pyridine N-oxide. A difference of reactivity between U/Pu and Np has been observed and has been attributed to the presence of a more covalent bond between Np and the carbene group in the transition state of formation of a transient carbene intermediate. [ABSTRACT FROM AUTHOR]