Syntheses structures and magnetic properties of heterometallic cobalt(II)-lanthanide complexes

  • 林 羽珊

Student thesis: Master's Thesis

Abstract

This work contains three parts The first part a series of heterometallic CoII–LnIII dinuclear [CoIILnIII(L1)2(μ2-ClO4)(H2O)4](ClO4)2·H2O (LnIII = TbIII (1·Tb) DyIII (2·Dy) HoIII (3·Ho) and ErIII (4·Er)) complexes have been synthesized by using multidentate ligands (L1) The structures of these compounds were determined by X-ray crystallography Structural studies demonstrate that the metal centers are bridged by perchlorate ligands leading to a [CoIILnIII(μ2-ClO4)] core Direct current (DC) magnetic susceptibility measurements reveal the presence of intramolecular ferromagnetic interactions in complexes 1·Tb-3·Ho However intermolecular antiferromagnetic interactions exhibit in complex 4·Er Alternating current (AC) magnetic susceptibility data indicate complexes 1·Tb-3·Ho exhibiting slow relaxations of the magnetization without dc field In the second part a series of heterometallic Co-Ln dinuclear [CoIILnIII(L2)2(MeOH)2(H2O)2Cl2]Cl·MeOH (LnIII = YIII (5·Y) TbIII (6·Tb) DyIII (7·Dy) and HoIII (8·Ho)) complexes have been obtained by using multidentate ligands (L2) The structures of these compounds were determined by X-ray crystallography DC magnetic susceptibility measurements reveal the presence of intramolecular ferromagnetic interactions between CoII and LnIII ions in complexes 6·Tb-8·Ho AC magnetic susceptibility data indicate complexes 6·Tb-8·Ho exhibit out-of-phase signals at zero dc field Besides the ac magnetic susceptibility data for complex 5·Y show a frequency-dependent relaxation under an applied field of 800 Oe This performance is consistent with field-induce SMM behaviors for high spin CoII ions Moreover for the complex 7·Dy single molecule magnet (SMM) behavior is displayed with a large thermally activated anisotropy barrier of 155 43 K without dc field It is the great Ueff (155 43 K) compare to all CoII-LnIII complexes that have been found so far The third part a novel series of defective dicubane 3d–4f tetranuclear [CoII2LnIII2(L3)2(μ3-OMe)2(MeOH)2(NO3)2(OAc)4]·xH2O·yMeOH (LnIII = YIII (9·Y) GdIII (10·Gd) TbIII (11·Tb) and DyIII (12·Dy); x = 0 y = 4 for 9·Y and 11·Tb; x = 2 y = 2 for 10·Gd and 12·Dy) complexes have been synthesized by using multidentate ligands (L3) DC magnetic susceptibility measurements reveal that the presence of spin-orbital coupling interactions in complexes 9·Y and ferromagnetic interactions between CoII and GdIII ions in complexes 10·Gd AC magnetic susceptibility data indicate that complexes 11·Tb and 12·Dy exhibit slow relaxation and QTM of the magnetization
Date of Award2017 Aug 23
LanguageEnglish
SupervisorHui-Lien Tsai (Supervisor)

Cite this

Syntheses structures and magnetic properties of heterometallic cobalt(II)-lanthanide complexes
羽珊, 林. (Author). 2017 Aug 23

Student thesis: Master's Thesis