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Updated: May 30, 2026

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes
Published on: June 24, 2022
Subtle effects control the polymerisation mechanism in α-diimine iron catalysts
Mikael P Johansson1, Marcel Swart
1Institut de Química Computacional and Departament de Química, Universitat de Girona, Campus Montilivi, ES-17071, Girona, Spain.
Abstract:
α-diimine iron complexes have been suggested to catalyse polymerisation via two distinct pathways, depending on the spin state of the iron complex. Here, we study a typical complex of this family, (R'')[N,N]FeCl(2), with [N,N] = Cy-N=CR''-CR''=N-Cy (Cy = cyclohexyl, R'' = PhF (para-fluorophenyl), PhOMe (para-methoxyphenyl), PhNMe(2) (para-dimethylaminophenyl). With R'' = PhF, PhOMe, polymerisation proceeds as a catalytic chain transfer (CCT) mechanism, with R'' = PhNMe(2), the polymerisation follows an atom transfer radical polymerisation (ATRP) pathway. Contrary to previous suggestions, we show that the spin-states of the complexes involved are not affected by the R'' group. Instead, the different behaviour arises from a subtle interplay between the electron-withdrawing or donating character of the reasonably distant phenyl substituent and the iron centre, and small but crucial differences in the reorganisation energies affected during the reactions.
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