Details

Autor(en) / Beteiligte

• Yao, Min-Xia
• Gao, Yu-Qi
• An, Zhong-Wu
• Zhu, Dong-Mei

Titel

The effect of magnetic coupling along the magnetic axis on slow magnetic relaxation in Dy complexes with configuration based on an aggregation-induced-emission-active ligand

Ist Teil von

• Dalton transactions : an international journal of inorganic chemistry, 2024-03, Vol.53 (11), p.5133-5146

Erscheinungsjahr

2024

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The adjustment of crystal symmetry and intramolecular magnetic coupling is of great importance for the construction of high-performance single-molecule magnets. By using an aggregation-induced-emission-active pyridine-carbohydrazone-based Schiff base ligand and phosphine oxides, four dinuclear and one one-dimensional Dy III -based complexes, [Dy 2 (TPE-pc) 2 (Bu 3 PO) 2 Cl 2 ]·2CH 3 CN·2H 2 O ( 1 ), [Dy 2 (TPE-pc) 2 (Cy 3 PO) 2 Cl 2 ] ( 2 ), [Dy 2 (TPE-pc) 2 (MePA) 2 Cl 2 ]·2CH 3 OH ( 3 ), [Dy 2 (TPE-pc) 2 (Ph 3 PO) 2 Cl 2 ] 2 ( 4 ) and [Dy 2 (TPE-pc) 2 (DPPO)Cl 2 ] n ( 5 ) (H 2 TPE-pc = ( E )- N ′-(2-hydroxy-5-(1,2,2-triphenylvinyl)benzylidene)picolinohydrazide, MePA = N -phenyl- N ′, N ′′-bis(morpholinyl) phosphoric triamide, DPPO = piperazine-1,4-diylbis(diphenyl phosphine oxide)), were isolated. All complexes are made up of an enol oxygen-bridged Dy 2 unit, where Dy III ions possess a pentagonal bipyramidal geometry with pseudo D 5h symmetry. Magnetic measurements reveal that intramolecular Dy III -Dy III couplings are ferromagnetic and all complexes display a significant slow magnetic relaxation phenomenon below 30 K under a zero dc field. Ab initio calculations indicate that the anisotropic magnetic axes of all Dy III ions are approximately perpendicular to the higher-order symmetric axes in all complexes, and that Dy III -Dy III magnetic couplings along the magnetic axes effectively suppress the ground state quantum tunneling effect of magnetization and promote the occurrence of slow magnetic relaxation. Raman relaxation prevails in all complexes. In addition, the H 2 TPE-pc ligand shows an aggregation-induced emission (AIE) effect; however, all complexes exhibit an aggregation-caused quenching (ACQ) phenomenon. By using an aggregation-induced-emission-active ligand, four dinuclear and one one-dimensional complexes based on Dy 2 unit with D 5h configuration were obtained. All complexes display significant slow magnetic relaxation behavior under zero dc field.