Photoisomerisable zero-field Co(II) single-ion magnets with azo-functionalized sulfonamide ligands: synthesis, crystal structure, magnetism and light-induced switching
Abstract
Three new zero-field Co(II) single ion magnets (SIMs) [Co(L¹)₂]•1.3MeOH (1), [Co(L²)₂]•0.33MeOH (2), and [Co(L³) 2 ] (3) and one Zn(II) analogue [Zn(L³)₂](Zn3) were synthesized using azo-derivatized N-sulfonylated amine ligands HL¹, HL² and HL³. All Co(II) complexes possess large axial magnetic anisotropy (Dexp = -61.2, -58.5, and -94.8 cm -1 for 1-3, respectively) with near-zero rhombicity stemming from axially elongated tetrahedral symmetry. Dynamic magnetic measurements revealed slow relaxation of magnetization up to 15 K for 1 and 2, and up to 18 K for 3 under a zero applied DC field, dominated by Raman and quantum tunneling processes. For complex 2, the Orbach process was additionally observed with U eff = 164.0 K (114.0 cm -1 ). Photoisomerisation experiments in solution and PMMA films demonstrated reversible light-induced switching for 1, 2, and Zn3 upon blue/UV irradiation, with no detectable degradation after ten cycles. These findings are further supported by DFT/TD-DFT calculations. Special attention is given to the study of non-covalent interactions in the vicinity of metal centres. To our knowledge, this represents the first report of light-switchable azo-functionalized zero-field Co(II) SIMs.
Related
- 1,3,4-Oxadiazole-sulfonamide hybrids: recent advances in biological activities, structure-activity relationships, and therapeutic applications.
- Stabilization of copper species on the functionalized magnetic metal-organic framework (Fe3O4@Zn-MOF-NH2-Cya@Cu) as a heterogeneous catalyst for synthesis of tetrahydrobenzopyran derivatives
- Environmentally benign synthesis of functionalized spiro[indoline-3,2'-pyrrole]-2,5'-diones via an aqueous-mediated squaric acid organocatalyzed protocol and their in vitro antimicrobial profiling.
- Modular synthesis of functionalized azetidines through visible-light copper-catalyzed carboamination of 1,3-dienes with azabicyclo[1.1.0]butanes
- Systematic Design and Synthesis of Methacrylate- and Trimethoxysilane-Functionalized POSS and DDSQ Nanostructures
BibTeX
@article{halas2026photoisomerisable,
title = {{Photoisomerisable zero-field Co(II) single-ion magnets with azo-functionalized sulfonamide ligands: synthesis, crystal structure, magnetism and light-induced switching}},
author = {Petr Halaš and Ivan Nemec and Erik Čižmár and Lucie Routaboul and Laure Vendier and Radovan Herchel},
journal = {Inorganic Chemistry Frontiers},
year = {2026},
month = sep,
doi = {10.1039/d6qi01825d},
url = {https://hal.science/hal-05745569v1},
note = {CC BY-NC 4.0},
}
RIS
TY - JOUR
TI - Photoisomerisable zero-field Co(II) single-ion magnets with azo-functionalized sulfonamide ligands: synthesis, crystal structure, magnetism and light-induced switching
AU - Petr Halaš
AU - Ivan Nemec
AU - Erik Čižmár
AU - Lucie Routaboul
AU - Laure Vendier
AU - Radovan Herchel
PY - 2026
DA - 2026/09/10
JO - Inorganic Chemistry Frontiers
DO - 10.1039/d6qi01825d
UR - https://hal.science/hal-05745569v1
AB - Three new zero-field Co(II) single ion magnets (SIMs) [Co(L¹)₂]•1.3MeOH (1), [Co(L²)₂]•0.33MeOH (2), and [Co(L³) 2 ] (3) and one Zn(II) analogue [Zn(L³)₂](Zn3) were synthesized using azo-derivatized N-sulfonylated amine ligands HL¹, HL² and HL³. All Co(II) complexes possess large axial magnetic anisotropy (Dexp = -61.2, -58.5, and -94.8 cm -1 for 1-3, respectively) with near-zero rhombicity stemming from axially elongated tetrahedral symmetry. Dynamic magnetic measurements revealed slow relaxation of magnetization up to 15 K for 1 and 2, and up to 18 K for 3 under a zero applied DC field, dominated by Raman and quantum tunneling processes. For complex 2, the Orbach process was additionally observed with U eff = 164.0 K (114.0 cm -1 ). Photoisomerisation experiments in solution and PMMA films demonstrated reversible light-induced switching for 1, 2, and Zn3 upon blue/UV irradiation, with no detectable degradation after ten cycles. These findings are further supported by DFT/TD-DFT calculations. Special attention is given to the study of non-covalent interactions in the vicinity of metal centres. To our knowledge, this represents the first report of light-switchable azo-functionalized zero-field Co(II) SIMs.
SN - 2052-1545
SN - 2052-1553
ER -