Coordination Atom Layout Optimizes The Magnetic Anisotropy Of Dysprosium Molecules

Single-molecule magnets(SMM)have attracted extensive attention in recent years due to their widely potential application in high-density information storage,quantum computers etc.After decades of development,lanthanide-based SMMs have emerged and made breakthrough progress.Among them,the research of mononuclear lanthanide SMM,also known as single ion magnet(SIM),has attracted more attention.However,the field is still facing many key scientific problems,such as low operating temperature and unfavorable relaxation process such as magnetization quantum tunneling(QTM).Fortunately,the quantum tunneling(QTM)process can be effectively suppressed in a crystal field environment with high symmetry.On the other hand,the introduction of magnetic exchange interactions to regulate the coordination field of the system can also play a key role in the magnetic relaxation behavior of rare earth single-molecule magnets.Therefore,in this paper,the local symmetry of the spin center and the coordination field are adjusted to achieve the purpose of controlling QTM and improving the magnetic relaxation behavior.The trivalent lanthanide ion is used as the spin carrier,and a series of?-diketone ligands are used.A series of Lanthanide tetra-?-diketone single-ion magnets were constructed with counter cations,and their magnetostructural relationships were studied.In addition,the complex 1 with superior properties in the system was selected to successfully anchor on the Ga N surface through ion exchange reaction,and its magnetic properties were researched.The main research work is as follows:1.A series of D_4dcomplexes with high local symmetry were synthesized us ing tetrabutylammonium chloride as the anti-cation and a series of?-diketone rar e earth salts.The main complexes formulas as[But₄N][Dy(DBM)₄](1),[But₄N][Dy(HPMBP)₄](2),[But₄N][Dy(BTFA)₄](3),Ga N-IM⁺-[Dy(DBM)₄]^-(4)(DBM=dibenzoylmethane,HPMBP=1-phenyl-3-methyl-4-benzoyl-2-pyrazolone,BTFA=benzoyltrifluoroacetone).The magnetic measurement results show that the comp lex 1 shows obvious slow magnetic relaxation behavior under zero field,and a h ysteresis loop is observed at 3 K.The effects of different local symmetry enviro nments on the slow relaxation behavior of the spin center were investigated by preparing complexes 2 and 3.The complex 1 with superior magnetic properties was selected and anchor on Ga N through ion exchange reaction,and a new type of hybrid material was obtained.The test of the loaded hybrid material through the traditional magnetic measurement system shows that the complex is successf ully loaded on the Ga N surface and the slow relaxation of the single-molecule magnet is observed.2.Using tetrahexyl ammonium chloride as the anti-cation,regulating?-diket one and central Lanthanide ion to obtain a series of complexes:[Hex₄N][Dy(DB M)₄](5),[Hex₄N][Tb(DBM)₄](6),[Hex₄N][Nd(DBM)₄](7),[Hex₄N][Dy(TTA)₄](8)(DBM=dibenzoylmethane,TTA=4,4,4-Trifluoro-1-(2-thienyl)-1,3-butanedion e Thenoyltrifluoroacetone),the test results of the magnetic properties of complexe s 5-8 showed obvious slow relaxation behavior.3.Based on the fixation of the first coordination sphere constructed by DBM,the influence of different anti-cations on the single-molecule magnetic properties of the complexes were investigated and a series of complexes were synthesized:[Et₄N][Dy(DBM)₄](9),[Ph CH₂N(CH₃)₃][Dy(DBM)₄](10).