Capping N-Donor Ligands Modulate the Magnetic Dynamics of DyIII β-Diketonate Single-Ion Magnets with D4d Symmetry

Peipei Cen; Xiangyu Liu; Jesús Ferrando-Soria; Yi-Quan Zhang; Gang Xie; Sanping Chen; Emilio Pardo

doi:10.1002/chem.201805608

Capping N-Donor Ligands Modulate the Magnetic Dynamics of Dy^III β-Diketonate Single-Ion Magnets with D_4d Symmetry

Chemistry. 2019 Mar 12;25(15):3884-3892. doi: 10.1002/chem.201805608. Epub 2019 Jan 29.

Authors

Peipei Cen^{1

2}, Xiangyu Liu^{3

2}, Jesús Ferrando-Soria², Yi-Quan Zhang⁴, Gang Xie¹, Sanping Chen¹, Emilio Pardo²

Affiliations

¹ Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of, Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, China.
² Departamento de Química Inorgánica, Instituto de Ciencia Molecular (ICMOL), Universidad de Valencia, Paterna, 46980, Valencia, Spain.
³ College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan, 750021, China.
⁴ Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing, 210023, China.

PMID: 30525257
DOI: 10.1002/chem.201805608

Abstract

A family of four mononuclear Dy^III β-diketonate complexes with formulas [Dy(tmhd)₃ (Br₂ -bpy) (1), [Dy(tmhd)₃ (Br-bpy)] (2), [Dy(tmhd)₃ (dppz)] (3), and [Dy(tmhd)₃ (mcdpq)] (4) (tmhd=2,2,6,6-tetramethyl-3,5-heptanedione, Br₂ -bpy=5,5'-dibromo-2,2'-bipyridine, Br-bpy=5-bromo-2,2'-bipyridine, dppz=dipyrido [3,2-a:2',3'-c]phenazine, mcdpq=2-methoxyl-3-cyanodipyrido[3,2-f:2,3'-h]quinoxaline) were prepared by modifying the capping N-donor coligands. Dy^III centers in these complexes feature an N₂ O₆ octacoordinate environment with distorted square-antiprismatic D_4d symmetry. Magnetic investigations evidenced single-ion magnet behavior in all complexes with energy barriers U_eff of 42.10 (1), 61.47, (2), 77.53 (3), and 2.51 K (4) in the absence of static field, as well as 206.03 (1), 224.13 (2), 247.76 (3), and 49.70 K (4) under applied dc field (H_dc =1500 Oe for 1 and 2; H_dc =1200 Oe for 3 and 4). The different natures of the N-donor ligands induce changes in both the coordination geometry and their intermolecular interactions, which severely impact their magnetic dynamics. The disparities in their magnetic behaviors and the uniaxial anisotropies are also explained and substantiated by theoretical calculations.

Keywords: N ligands; lanthanides; ligand effects; magnetic properties; single-ion magnets.