What question did this study set out to answer?

The aim is to explore the redox behavior and magnetic properties of copper(II) verdazyl complexes.

April 12, 2026

Redox Switching of Magnetic Anisotropy in Copper(II) Verdazyl Systems

Key Points

The aim is to explore the redox behavior and magnetic properties of copper(II) verdazyl complexes.
Synthesis of the neutral species [Cu(dipyvd)2] using copper(II) triflate and dipyvdH.
Oxidation of [Cu(dipyvd)2] in two one-electron steps to produce [Cu(dipyvd)2]+ and [Cu(dipyvd)2]2+.
Characterization of the three species using high-field/high-frequency EPR measurements and DFT calculations.
[Cu(dipyvd)2] undergoes oxidation to form two positively charged species with distinct magnetic properties.
Significant exchange coupling indicates ferromagnetic interactions between the ligands and copper ion.
ZFS parameters show anisotropic behavior upon oxidation, indicating changes in magnetic anisotropy.

Abstract

Reaction of copper(II) triflate with 1-isopropyl-3,5-di(2'-pyridyl)-6-oxo-2H-tetrazine (dipyvdH) and triethylamine gave the neutral species Cu(dipyvd)2. Cu(dipyvd)2 can be oxidized in two one-electron steps, leading to Cu(dipyvd)2+ and Cu(dipyvd)22+ isolated as their PF6- salts. All three species are best formulated as copper(II) compounds with localized anionic diamagnetic, or neutral radical ligands. Exchange coupling between the neutral radical ligands and the copper(II) ion is strongly ferromagnetic, leading to S = 1 and S = 3/2 ground states for Cu(dipyvd)2+ and Cu(dipyvd)22+, respectively. High-field/high-frequency EPR (HF-EPR) measurements reveal that, upon oxidation, the copper(II) complexes become anisotropic, with zero-field splitting (ZFS) parameters of D = 4.5 cm-1, E/D = 0.04 for Cu(dipyvd)2+ and D = 1.5 cm-1, E/D = 0.3 for Cu(dipyvd)22+. DFT calculations suggest that the major component of the ZFS tensor for Cu(dipyvd)2+ is aligned with the Jahn-Teller elongation axis of the cations.

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