- By:
- Hand, Adam; Fakolujo, Adiat; Krzystek, J; Ozerov, Mykhaylo; Daemen, Luke; Xing, Jie; Gai, Zheng ; Jin, Rongying; Telser, Joshua; Podlesnyak, Andrey A; Xue, Zi-Ling
- Journal Name:
- New Journal of Chemistry
- Volume:
- TBD
- Publication Date:
- August 27, 2025
- View DOI Listing:
- https://doi.org/10.1039/D5NJ01857A
Abstract
High-spin CoII complex (PPh4)2[Co(N3)4] (Co-N3) has been investigated using advanced spectroscopic techniques [far-IR magneto-spectroscopy (FIRMS), high-frequency and -field EPR (HFEPR), and inelastic neutron scattering (INS)] to study its zero-field-splitting (ZFS), giving spin-Hamiltonian (SH) parameters. The analysis of multi-frequency HFEPR reveals the easy-axis anisotropy with a D value of –10.39(5) cm-1 and rhombic ratio (E/D) of 0.21(1). The magnetic properties have also been probed by direct current (DC) magnetometry, suggesting minor differences in anisotropy from the previously reported polymorph (Co-N3'). Ligand-field theory (LFT) analysis indicates the structures of Co-N3 and Co-N3' are closer to D2d symmetry than other symmetries considered. Alternate current (AC) susceptibility reveals slow magnetic relaxation under an applied field, indicating Co-N3 is a field-induced single-ion magnet (SIM). While both Co-N3 and Co-N3' were studied by DC magnetometry, one unusual aspect of the current work on Co-N3 is that advanced spectroscopies HFEPR, FIRMS, and INS were used to directly observe transitions between ZFS split states, giving accurate SH parameters.
