| With the in-depth study of bistable molecular materials by scientists,people have gradually realized that the research of molecular bistable has not only made important progress on the basic level,but also has made major breakthroughs in the application prospects of molecular device materials.This thesis is dedicated to the design and synthesis of photomagnetic bistable complexes,and a series of new complexes have been synthesized through the preparation methods such as diffusion method and layered method.The single crystal structure of these complexes was tested by X-ray single crystal diffraction,and their near-infrared luminescence and magnetic properties were investigated respectively.The specific content is as follows:(1)A series of heterometallic complexes azo-Zn2Ln2([Zn2Ln2(azo-L)4Cl2],Ln=Eu(1),Yb(2),Er(3),Dy(4),Ho(5),Tb(6),Gd(7)).The single crystal structure,ultraviolet-visible light spectrum and solid-state fluorescence spectrum of complexes 1-7 were studied in detail.X-ray single crystal diffraction confirmed that the complexes 1-7 have the same structure,and all contain four azobenzene units coordinated.UV-visible spectroscopy studies have found that the complex transforms from trans to cis structure under ultraviolet light irradiation;it returns to trans structure under heating or dark conditions,and the obvious color change can be observed by the naked eye.Near-infrared fluorescence exploration found that the ligand azo-H2L can sensitize lanthanide ions(such as Yb3+,Er3+)that emit light in the near-infrared range.It shows a clear near-infrared emission peak.Interestingly,near-infrared luminescence can be adjusted by crystalline photochromism.(2)With imidazole-based ligand(bibe)and triazole-based ligand(btmb)as main ligands,potassium thiocyanate(KSCN)and sodium dicyanamide(DCA)as auxiliary ligands,and transition metal Fe2+by diffusion method Three new complexes were synthesized:[Fe(bibe)4(SCN)2]n(8),[Fe(DCA)2(CH3OH)4]n(9)and[Fe(btmb)2(DCA)2(CH3OH)2]n(10).The single crystal structure of complexes 8-10 was tested by X-ray single crystal diffraction.Complexes 8 and 9 are both two-dimensional planar complexes,and complex 10 has a one-dimensional chain structure.Crystallographic data show that complexes 8-10 are in a high-spin state at low temperatures.Through UV-visible spectroscopy studies,it is found that the complex 10 has a strong adsorption effect on the anionic dye Eosin(EY),and the obvious changes can be observed by the naked eye.The complex 10 has application prospects in the adsorbent.(3)Three ligands based on the luminescent group BPVB,1,4-bpy,AnPy2 were synthesized,with AnPy2 as the main ligand,potassium selenocyanate(KSeCN)as the auxiliary ligand,and transition metal Fe2+through a layered method.New complex:[Fe(AnPy2)2(SeCN)2]n(11).The single crystal structure of complex 11 was tested by X-ray single crystal diffraction,and it was determined that complex 11 was a two-dimensional planar complex.The crystallographic data showed that complex 11 was in a high-spin state at low temperatures. |
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