| With the rapid development of luminescent materials and digitization,Ln-based complexes are widely used in luminescence,sensing,biological activity and molecular magnetism.Monomolecular magnet is an important part of magnetic material.In recent years,great breakthroughs have been made in the magnetic blocking temperature and flip energy barrier of dysprosion-based single-molecule Magnets?SMMs?,leading to the closer application of SMMs in the fields of high-density information storage,quantum computing and molecular spintronics.This paper mainly relies on the cyclohexandiamine derivatives ligands with good photoluminescence properties to construct the response type and multifunctional dysprosium based complexes in a directional way,and further studies their magnetic structure relations and photoluminescent response structure-activity relations.This paper attempts to summarize the synthesis method and the optimal reaction conditions,and explores the assembly rules,provide examples for the further design and synthesis of more sensitive responsive magnetic materials and multifunctional dysprosium based complexes.The first chapter is introduction,introduced the selected topic significance and scientific contribution of this paper,mainly introduced the rare earth base the development of single molecule magnets,multi-function research status of lanthanide complexes?photoluminescence type rare earth base on single molecular magnets?,intelligent latest research progress of lanthanide magnetic material,etc.,as this paper provides a solid foundation for the further development of.In chapter 2,we used 3-methoxysalicylaldehyde,1,2-cyclohexanediamine,and Dy?NO3?3·6H2O to react under a solvothermal condition?CH3OH:CH3CN=1:1?at 80°C to obtain a butterfly-shaped tetranuclearDy?III?cluster[Dy4?L1?4??3-O?2?NO3?2]?1,H2L1=6,6'-??1E,1'E?-?cyclohexane-1,3-diylbis?azanylylidene??bis?methanylylidene??bis?2-methoxyphenol??.H2L1 was obtained by the in situ Schiff base reaction of 3-methoxysalicylaldehyde and1,2-cyclohexanediamine.The four Dy?III?ions are in two coordination environments:O9?Dy1?and N2O6?Dy2?.Magnetic studies show that the cluster Dy4 exhibits single-molecule magnet behavior under zero-field conditions.We changed 3-methoxysalicylaldehyde to 3-ethoxysalicylaldehyde and obtained one case of hydrogen-bonded helix frameworks[Dy?H2L2??NO3?3]n 2,H2L2=6,6'-??1E,1'E?-?cyclohexane-1,3-diylbis?azanylylidene??bis?methanylylidene??bis?2-ethoxyphenol?)under the same reaction conditions.The ligand H2L2 was formed by the in situ Schiff base reaction of 3-ethoxysalicylaldehyde and 1,2-cyclohexanediamine.The compound is the first Dy-base hydrogen-bonded helix framework formed by the metal spiral chain connected by hydrogen bonding.Magnetic studies show that 2 exhibit single-ion magnet behavior.The energy barrier and extrapolated relaxation times are Ueff=115 K and?0=2.05×10-7 s,respectively,under 0 Oe DC field and Ueff=137 K and?0=1.02×10-8 s,respectively,under 800 Oe DC field.In chapter 3,The design and synthesis of simple lanthanide complexes with multiple functions have been widely concerned and have certain challenges.Herein,we successfully synthesized a seriesofbinuclearlanthanidecomplexes[Ln2?L3?2?NO3?4]?HL3=2-amino-1,2-di?pyridin-2-yl?ethanol;Ln=Dy,3;Tb,4;Ho,5;Er,6?via the in situ self-condensation of Ln?NO3?3·6H2O-catalyzed 2-aminomethylpyridine?16 steps?under solvothermal conditions.3was mixed with different volatile organic solvents,and photoluminescence tests demonstrated that it showed excellent selective photoresponse to chloroform?CHCl3?.Sensing 4 on different organic solvents under the same conditions showed that it exhibited excellent selective photoresponse to methanol?CH3OH?.Even under EtOH conditions,4 could selectively respond to small amounts of CH3OH.To the best of our knowledge,achieving selective photoresponse to various volatile organic compounds by changing the metal center of the complex is difficult.Furthermore,we performed anti-counterfeiting test on 4,and the results showed significant differences between the anti-counterfeiting marks under white light and ultraviolet light conditions.The alternating current susceptibilities of 3 suggested that it was a typical single-molecule magnet(Ueff=87 K and?0=1.84×10-6 s)under a 0 Oe dc field.Ab initio calculations on 3 indicated that the high degrees of axiality of the constituent mononuclear Dy fragments are the main reason for the existence of SMM behavior.In chapter 4,a series of mononuclear lanthanide complexes[Ln?HL4??NO3?3],?Ln=Dy?III?,7;Tb?III?,9;Eu?III?,10andGd?III?,11?,HL4=?N1E,N2E?-N1,N2-bis??1-methyl-1H-benzo[d]imidazol-2-yl?methylene?cyclohexane-1,2-diamine)is obtained by reacting N-methylbenzimidazole-2-carbaldehyde and 1,2-cyclohexanediamine?HL1?with Ln?NO3?3·6H2O under solvothermal conditions.HL4 ligand is produced via an in situ Schiff base reaction of two molecules of N-methylbenzimidazole-2-carbaldehyde and one molecule of L1.The metal center Ln?III?is coordinated in a N4O6 environment formed by L4 and NO3-.NaSCN is added on the basis of 7 synthesis.One SCN-replaces one of the three coordinated NO3-anions in 7,and the complex[Dy?HL4??NO3?2?SCN?]·CH3CN 8 was obtained.7 shows an excellent luminescence response to petroleum ether?PET?,an organic solvent.To the best of our knowledge,this study is the first to use a complex for sensing responses to PET.When the metal center is changed,the obtained mononuclear complexes 9 and 10 show an excellent luminescence response to tetrahydrofuran?THF?.Lastly,8 obtained by changing the coordinating anion shows an excellent luminescence response to dichloromethane.Herein,for the first time,we regulate the metal center and coordinating anion of lanthanide complexes to adjust the recognition and response of these complexes to different organic solvents. |
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