The Research Of Near Infrared Luminescent In 5-carboxyl Salicylic Aldehyde Schiff Base Dinuclear Complexes

Rare earth complexes have important applications in fluorescence immunity analysis,medical diagnosis and optical amplifier.The characteristic spectral lines of rare earth ions Er3+?Nd3+?Yb3+ have the following features: narrow line width,small background,high strength.So the near infrared luminescent materials of Er3+,Nd3+and Yb3+were widely used in laser,optical fiber communication and the diagnosis of near infrared light-emitting.In this article,firstly three kinds of ligands were synthesised.5-carboxyl salicyl aldehyde shrinkage ethylenediamine(L1)was synthesised by 5-carboxyl salicylaldehyde and ethylenediamine,5-carboxyl salicylaldehyde shrinkage diethylenetriamine(L2)was synthesised by 5-carboxyl salicylaldehyde and diethylenetriamine,5-carboxyl salicylaldehyde shrinkage triethylenetetramine(L3)was synthesised by 5-carboxyl salicylaldehyde and triethylenetetramine;secondly they were respectively ? sed to synthesis transition metal complexes with transition metal salts(transition metal salt:Fe(NO3)3,CoCl2,Zn(CH3COO)2,Mn(CH3COO)2,Cu(NO3)2,NiCl2).The obtained transition metal complexes was written as L1-M,L2-M,L3-M(M: Fe,Co,Zn,Mn,Cu,Ni);thirdly the obtained transition metal complexes were coordinated with rare earth ions(Er3+,Nd3+,Yb3+)to get the three series of d-f hetero-dinuclear metal complexes,which can be written as L1-M-Ln,L2-M-Ln,L3-M-Ln(Ln: Er,Nd,Yb).And these complexes were characterized by infrared spectrum,ultraviolet spectrum,the near infrared spectra,time-resolved fluorescence decay curve.From the results of IR spectrum,the characteristic peaks of complexes had shifted,in contrast with that of ligand.It implies that the coordination bond has been formed.Andthis conclusion can also be proved by ultraviolet spectrum.Excitation into the organic chromophores(583 nm for all complexes)result in characteristic near-IR luminescence from the Nd3+,Er3+,Yb3+centers in solid state,the intensity of some d-f hetero-dinuclear metal complexes were measured.It is easy to conclude that the fluorescence intensity of Yb3+complexes is generally higher than others.The Fluorescence lifetime of some d-f hetero-dinuclear metal complexes were also measured.Time-resolved fluorescence decay curve were made.Fluorescence lifetime were fitted by the method of single exponential function.Compared with the Er complexes,the fluorescent lifetime of Yb complexes were almost twice than the former,the fluorescent lifetime of L1-Fe-Yb is the longest.The quantum yield of L1-Fe-Yb complex is also maximum.The obtained d-f dinuclear metal complexes with the feature of strong near infrared light emitting intensity and long fluorescent life time can be used as good fluorescent materials.Such as: L1-Fe-Yb,L1-Zn-Yb,L2-Zn-Yb,L2-Fe-Yb.