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Updated: Jul 30, 2025
Fabrication Procedures and Birefringence Measurements for Designing Magnetically Responsive Lanthanide Ion Chelating Phospholipid Assemblies
Published on: January 3, 2018
Tuning the optical and magnetic properties of lanthanide single-ion magnets using nitro-functionalized
Christopher Hossack1, Folasade Abdul1, Christopher Cahill1
1Department of Chemistry, The George Washington University, 800 22nd Street, NW, Washington, D.C. 20052, USA. chossack@gwu.edu.
Abstract:
We report the synthesis, crystal structures, photophysical and magnetic properties of 11 novel lanthanide complexes with the asymmetrically functionalized trispyrazolylborate ligand 4-nitrotrispyrazolylborate, 4-NO2Tp-: [Ln(4-NO2Tp)3] (Ln = La-Dy, except Pm). In-depth photophysical characterization of the ligands via luminescence, reflectance and absorption spectroscopic techniques, decay lifetimes, quantum yields supported by time-dependent density functional theory (TD-DFT) and natural bond order (NBO) analysis reveal that n-NO2Tp- ligands are dominated by intra-ligand charge transfer (ILCT) transitions and that second-sphere interactions are critical to the stabilization of the T1 state of n-NO2Tp- ligands and hence their ability to sensitize Ln3+ emission. The luminescence properties of the complexes indicate that 4-NO2Tp- is a poor sensitizer of Ln3+ emission, unlike 3-NO2Tp-. Moreover, [Nd(4-NO2Tp)3] (crystallized as a hexane solvate) displays single-molecule magnet (SMM) properties, with longer relaxation times and larger barrier than the non-functionalized [NdTp3], attributed to the addition of the NO2-group and subsequent rigidification of the molecular structure.
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