Influence of noncovalent cation/anion-π interactions on the magnetic exchange phenomenon

Abstract

The role of noncovalent ion-π interactions in controlling the intramolecular magnetic exchange interaction in 1,3-phenylene-based bis(aminoxyl) diradical has been investigated computationally through deploying an external ion in the vicinity of the π-cloud of the phenylene coupler. Using spin-polarized hybrid density functional theory-based calculations, we observe that the anions drastically enhance the magnetic exchange interaction for distances below the equilibrium distance. The phenomenon could be understood by two simultaneously occurring effects, which influence the intramolecular magnetic exchange interaction. The first one is the enhancement of the paratropic current density on the aryl couplers due to a small amount of charge transfer. The other one is the attainment of magnetization density on the anionic species due to such charge transfer, favorably altering the magnetic exchange pathway. The achieved understanding provides prospects of a completely new strategy of enhancing the intramolecular ferromagnetic coupling through the assistance of external ionic species inserted in molecular crystals. © 2011 American Chemical Society.

Publication Title

Journal of Physical Chemistry Letters

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