title: Lanthanide dinuclear complexes constructed from mixed oxygen-donor ligands: the effect of substituent positions of the neutral ligand on the magnetic dynamics in Dy analogues.
abstract: Two series of lanthanide dinuclear complexes with the general formulae, [Ln(n-PNO)(Bza)3(H2O)] {Bza = benzoic acid; n = 3, n-PNO = 3-picoline N-oxide, Dy(1) and Er(2); and n = 4, n-PNO = 4-picoline N-oxide, Nd(3), Eu(4), Gd(5), Tb(6), Dy(7), Er(8) and Y(9)} have been successfully synthesized by the hydrothermal method. Single-crystal X-ray diffraction experiments illustrate that the two series of compounds possess similar carboxylic ligand-bridged dinuclear structure and coordination geometry around the lanthanide ions despite the different methyl-substituent positions on the neutral ligand. Comparative studies of the Dy analogues in the static-field measurements reveal only a little difference with a small butterfly-shaped opening for complex 1 and a close hysteresis loop for 7 at 2.0 K. However, systematic investigations of the alternating-current (ac) measurements indicate that the different substituent positions of the picoline N-oxide ligand have a significant effect on the magnetic relaxation dynamics. A more substantial suppression of the quantum tunnelling of magnetization (QTM) effect and pronounced slow magnetic relaxation were observed in complex 7 as compared to 1 under both zero and a 1 kOe static field.
authors: Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, PR China. zhuwenhua@pku.org.cn.
authors: Wen-Hua
authors: WH
authors: Zhu
authors: Shan
authors: S
authors: Li
authors: Chen
authors: C
authors: Gao
authors: Xia
authors: X
authors: Xiong
authors: Yan
authors: Y
authors: Zhang
authors: Li
authors: L
authors: Liu
authors: Annie K
authors: AK
authors: Powell
authors: Song
authors: S
authors: Gao