| In the past 20 years,the low-nuclearity complexes constructed by lanthanide metals have received extensive attention and research because of their unique structural characteristics,optical properties and magnetic properties,and gained more experimental and theoretical knowledges.Here,according to this hot spot,we have synthesized several series of low-nuclearity rare earth metal complexes by means of room temperature self-assembly,using X-ray crystal diffraction,infrared spectroscopy?IR?,elemental analysis,and solid powder diffraction.The technology is simply characterized and tested,and the magnetic properties of these low-nuclearity complexes are also tested and explored.Among them:1.The Schiff base ligand?HL1?obtained by the condensation of5-bromosalicylaldehyde and 8-aminoquinoline reacted with the rare earth metal salt Ln?NO3?·6H2O and the auxiliary ligand sodium butyrate to obtain a series of binuclear complexes,namely[Ln2?L1?2?CH3CH2CH2COO?2?NO3?2?MeOH?2]?Ln=Gd?1?,Tb?2?,Dy?3?,Ho?4??.They were characterized by their structural and magnetic properties.The magnetic data indicates that the Dy cluster has a clear frequency-dependent magnetic behavior,which indicates that there is a slow magnetic relaxation effect,and complex 2 is calculated by the Arrhenius formula.The pre-exponential factor of complex 2 is?0=4.12×10-66 s,and the energy barrier is27.08 K.Therefore,complex 2 may be a single molecule magnet.2.A series of mononuclear complexes were obtained by reacting the Schiff base ligand HL1 with a rare earth metal salt Ln?NO3?·6H2O and an ancillary ligand sodium azide,namely[Tb?L1?2NO3MeOH]?5?,[Dy?L1?2NO3H2O]?6?,[Ho?L1?2NO3]X·H2O?7?.They were characterized by their structural and magnetic properties.The magnetic data indicates that the Dy cluster has a clear frequency-dependent magnetic behavior,which indicates that there is a slow magnetic relaxation effect,and the pre-exponential factor of the complex 6 calculated by the Arrhenius formula is?0=2.70×10-6s,the energy barrier is 14.41 K.Therefore,the complex 6 may be a single molecule magnet.3.A series of dinuclear complexes were obtained by reacting Schiff base ligand HL2 obtained by condensation of 3-methoxysalicylaldehyde and benzoylhydrazide with rare earth metal salt Ln?NO3?·6H2O and an auxiliary ligand sodium pivalate,namely[Ln2?L2?2?NO3?2?piv?2]?Ln=Tb?8?,Dy?9?,Ho?10??.They were characterized by their structural and magnetic properties.The magnetic data indicates that the Dy cluster has a clear frequency-dependent magnetic behavior,which indicates that there is a slow magnetic relaxation effect,and the complex 9 is calculated by the Debye formula.The pre-factor is?0=2.26×10-66 s and the energy barrier is 7.28 K.Therefore,the complex 9 may be a single molecule magnet. |
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