Highly Coordinated Mononuclear And Dinuclear Dy-based Single-molecule Magnets

Single-molecule magnets（SMMs）are molecules that can be magnetized under a magnetic field and retain their magnetism after removal of the magnetic field,embodying the optimal size for spin-based information storage,and have potential applications in high-density information storage,quantum information processing,and molecular spintronics.Lanthanide-based single-molecule magnets have attracted increasing research interest due to their large magnetic anisotropy and high ground-state spins.Among the lanthanide-based single-molecule magnets that have been synthesized so far,Dy^Ⅲ single-molecule magnets have the highest number of properties and have been widely used to construct single-molecule magnets with significant magnetic properties.In this thesis,mononuclear and binuclear Dy^Ⅲsingle-molecule magnets are investigated in detail as follows:1.Single-crowned tetragonal antiprismatic mononuclear Dy^Ⅲ single-molecule magnetA mononuclear Dy^Ⅲ complex[Dy^ⅢL（CH₃O）]（BPh₄）（1）was successfully constructed and characterized as a nine-coordinated monocrown tetragonal anti-prismatic conformation by using a"pocket"shaped bulk octodentate ligand L（L=1,4,7,10-tetra（2-pyridylmethyl）-1,4,7,10-tetraazacyclododecane）coordinated to a Dy^Ⅲ ion and methoxy bonded to the Dy^Ⅲion at the opening of the"pocket".The crystal structure and magnetic data indicate that the combination of a strong axial ligand field and a weak equatorial plane ligand field constructs a pseudo-monocollinear linear Dy-O ligand field of Dy^Ⅲ monomolecular magnet with significant magnetic anisotropy.2.Hexagonal bipyramidal dinuclear Dy^Ⅲ single-molecule magnetA Dy^Ⅲ binuclear complex[Dy₂^ⅢB（EO5）₂（Cl₂NO₂PhO）₄]（BPh₄）·CH₂Cl₂（2）was successfully constructed using pentaglycol as an equatorial ligand and 2,6-Dichloro-4-nitrophenol as an axial ligand coordinated to the Dy^Ⅲ ion,with one boron atom from sodium tetraphenylboron and four oxygen atoms from two pentaglycols bridging the two Dy^Ⅲ ions.Magnetic studies showed that complex 2 has significant magnetic anisotropy and exhibits the slow magnetic relaxation behavior under zero DC field.3.Dimethyl phosphate bridged dinuclear Dy^Ⅲ single-molecule magnetA Dy^Ⅲ binuclear complex[Dy₂^Ⅲ（L²）₂（PO₄C₂H₆）₄]（BPh₄）₂[（C₂H₅）₃OH]（3）was successfully constructed and characterized by using a pentadentate macrocyclic ligand L²（L²=2,14-dimethyl-3,6,10,13,19-pentaazabicyclo-1,2,13,15,17-pentene）as an equatorial ligand to coordinate with Dy^Ⅲ ions,each Dy^Ⅲ ion forming an eight-ligand conformation,and then using dimethyl phosphate to double-bridge the two Dy^Ⅲ ions.Magnetic studies have shown that complex 3 has relatively high magnetic anisotropy and exhibits a slow magnetic relaxation behavior induced by magnetic fields.