Ionic liquid modification of radical catalyst: Ab initio molecular dynamics and metadynamics
Vahideh ALIZADEH1, Barbara KIRCHNER1
1Mulliken Center for Theoretical Chemistry, University of Bonn, Bonn, Germany
Due to the high abundance and low toxicity of the metal, the use of titanium catalysts is
extremely attractive for the development of sustainable reactions. Titanocene (III) based
"metalloradical catalysis" merges the advantages of radical chemistry with those of
traditional metal catalysis.[1] Such catalytic reactions are usually performed in a liquid
phase and can be influenced by the medium (solvent).[2] Ionic liquids (ILs) are a fascinating
class of solvents for catalytic reactions as they possess a wide liquid range at low
temperatures and are entirely composed of mobile ions. [3]
In this regard, ILs have already shown great potential in stabilizing radicals and directing
reactions.[2] Computational methods can provide valuable insights for the fundamental
understanding of medium effects on metalloradical catalysis and support the rational design
of new catalysts and reactions. Here, we use state-of-the-art ab initio molecular dynamics
simulations (AIMDs) and metadynamics[4] to unravel the reactive species of the catalyst,
the mechanisms of radical stabilization, and the structures of ionic transition states or
intermediates which occur during the reaction.
From our investigations, we observe a great tunability of the catalyst structure when using
different ILs, leading to a potential avenue for controlling metalloradical catalysis activity
and providing new routes to increase the desired outcome of catalytic reactions.
References
[1] R. Richrath, T. Olyschläger, S. Hildebrandt, D. Enny, G. Fianu, R. Flowers, A. Gansäuer,
Chem. Eur. J., 24, 6371-6379 (2018)
[2] B. Kirchner, J. Blasius, V. Alizadeh, A. Gansäuer, O. Hollóczki, J. Phys. Chem. B, 126,
766-777 (2022)
[3] O. Hollóczki, F. Malberg, T. Welton, B. Kirchner, Phys. Chem. Chem. Phys. 16, 16880 -
16890.(2014)
[4] A. Barducci, M. Bonomi, M. Parrinello, WIREs. Comput. Mol. Sci., 1, 826-843 (2011)