| Titre : |
Supramolecular and functionnal architectures : towards efficient magnets |
| Type de document : |
texte imprimé |
| Auteurs : |
Bretosh, Kateryna, Auteur ; Jean-Pascal Sutter, Directeur de thèse ; Béreau, Virginie, Directeur de thèse |
| Année de publication : |
2019 |
| Langues : |
Anglais (eng) |
| Tags : |
FE(II) - NI(II) - MAGNETIC ANISOTROPY - SCM - SMM - HEPTACOORDINATE - MOLECULAR MAGNETISM |
| Résumé : |
"This thesis deals with the control of magnetic anisotropy in the design of molecule-based magnetic materials. Magnetic anisotropy is highly related to the coordination environment of a metal ion. Herein we focused on 3d metal ions with pentagonal bipyramid coordination spheres that may exhibit a rather large magnetic anisotropy. A series of seven coordinate Fe(II) and Ni(II) complexes formed with a neutral pentadentate cyclic ligand (LN5PhenMe) were synthesized and their magnetic behaviors investigated. They have been found to exhibit axial (Ising-type) magnetic anisotropy with a negative zero-field splitting axial parameter D. Modulation of magnetic anisotropy was studied for Fe(II) complexes with various substituents in axial position (Fe(II)LN5PhenMeX2, where X= Cl-, Br- , I-, NCS-, ROH, {Ni(CN)4}2-) revealing D values spanning from ca -4 to -17 cm-1. Due to the large axial anisotropy induced by heavier halogen atoms in Br and I derivatives, these complexes showed SMM (Single Molecular Magnet) properties with energy barrier Ueff/kB ~ 70 K. These complexes are structurally robust and can be used as building units to form polynuclear systems. Their combination with a related trans-cyano K[CrLN3O2Ph(CN)2] complex allowed the synthesis of trinuclear complexes [{CrLN3O2Ph(CN)2}2MLN5PhenMe] (M= Fe(II) or Ni(II)), and a 1-D coordination polymer [{CrLN3O2Ph(CN)2}MLN5PhenMe][ClO4]n showing respectively, SMM and SCM (Single Chain Magnets) behaviors. The latter is the first example of SCM made with pentagonal bipyramid Ni centers." |
| Document : |
Thèse de Doctorat |
| Etablissement_delivrance : |
Université de Toulouse 3 |
| Date_soutenance : |
29/10/2019 |
| Ecole_doctorale : |
Sciences de la Matière (SdM) (Toulouse) |
| Domaine : |
Chimie Organométallique et de Coordination |
| Localisation : |
LCC |
| En ligne : |
http://thesesups.ups-tlse.fr/4681/ |
Supramolecular and functionnal architectures : towards efficient magnets [texte imprimé] / Bretosh, Kateryna, Auteur ; Jean-Pascal Sutter, Directeur de thèse ; Béreau, Virginie, Directeur de thèse . - 2019. Langues : Anglais ( eng)
| Tags : |
FE(II) - NI(II) - MAGNETIC ANISOTROPY - SCM - SMM - HEPTACOORDINATE - MOLECULAR MAGNETISM |
| Résumé : |
"This thesis deals with the control of magnetic anisotropy in the design of molecule-based magnetic materials. Magnetic anisotropy is highly related to the coordination environment of a metal ion. Herein we focused on 3d metal ions with pentagonal bipyramid coordination spheres that may exhibit a rather large magnetic anisotropy. A series of seven coordinate Fe(II) and Ni(II) complexes formed with a neutral pentadentate cyclic ligand (LN5PhenMe) were synthesized and their magnetic behaviors investigated. They have been found to exhibit axial (Ising-type) magnetic anisotropy with a negative zero-field splitting axial parameter D. Modulation of magnetic anisotropy was studied for Fe(II) complexes with various substituents in axial position (Fe(II)LN5PhenMeX2, where X= Cl-, Br- , I-, NCS-, ROH, {Ni(CN)4}2-) revealing D values spanning from ca -4 to -17 cm-1. Due to the large axial anisotropy induced by heavier halogen atoms in Br and I derivatives, these complexes showed SMM (Single Molecular Magnet) properties with energy barrier Ueff/kB ~ 70 K. These complexes are structurally robust and can be used as building units to form polynuclear systems. Their combination with a related trans-cyano K[CrLN3O2Ph(CN)2] complex allowed the synthesis of trinuclear complexes [{CrLN3O2Ph(CN)2}2MLN5PhenMe] (M= Fe(II) or Ni(II)), and a 1-D coordination polymer [{CrLN3O2Ph(CN)2}MLN5PhenMe][ClO4]n showing respectively, SMM and SCM (Single Chain Magnets) behaviors. The latter is the first example of SCM made with pentagonal bipyramid Ni centers." |
| Document : |
Thèse de Doctorat |
| Etablissement_delivrance : |
Université de Toulouse 3 |
| Date_soutenance : |
29/10/2019 |
| Ecole_doctorale : |
Sciences de la Matière (SdM) (Toulouse) |
| Domaine : |
Chimie Organométallique et de Coordination |
| Localisation : |
LCC |
| En ligne : |
http://thesesups.ups-tlse.fr/4681/ |
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