The study of the rare earth complexes continues to be an active research area

which may be attributed to the specific spectroscopic and magnetic properties of rare earth ions and the abundance of rare earth elements in our country.Amide type podands

which are flexible in structure and have‘terminal-group effects’

will shield the encapsulated rare earth ion from interaction with the surroundings effectively

and thus achieve strong luminescent properties.The fluorescence intensities of Eu and rib complexes

which exhibit the characteristic emissions of Eu

3+

and Tb

3+

respectively

can be increased by mixing with some non-fluorescent ions quantificationally and their costs can be also decreased.So

in our work the white complexes of Eu

3+

Tb

3+

1/2Eu

3+

and 1/2RE

3+

1/2Tb

3+

and 1/2RE

3+

(RE

3+

=La

3+

Gd

3+

Y

3+

) with 1

6-bis[(2′-benzylaminoformyl) phenoxyl]hexane (L) have been synthesized in the solution of ethyl acetate and chloro-form. The elemental analysis shows that Eu and Th complexes conform to a 2:3 metal-to-ligand stoichiometfies 2RE(NO

3

)

3

·3L·nH

2

O(

RE

=La

n

=2;

RE

=Eu

Gd

Tb

Y

n

=4).Their IR spectra are recorded on a Bruke FTS66V/S spectrophotometer with KBr pellet in the range of 400～4 500 cm

-1

.The results indicate that all complexes have similar IR spectra

of which the characteristic bands have similar shifts

suggesting that they have a similar coordination structure.Their UV-VIS spectra are recorded on a Hitachi U-3010 spec-trophotometer and show that mixed with identical molar ratio of La

the absorbance of Eu-La mixed complex is lower than that of Eu complex. Fluorescence spectra of the complexes were carried out on a Hitachi F-4500 spectrophotometer at room temperature.The excitation and emission slit widths are 1.0 nm.The best excitation wavelengths for Eu and Tb complexes are 396 nm and 320 nm respectively.It can be concluded from the results that mixed with identical molar ratio of La

3+

Gd

3+

and Y

3+

Eu (NO

3

)

3

and Th(NO

3

)

3

complexes exhibit the characteristic emissions of Eu

3+

and Tb

3+

respectively and their fluorescence intensities are sensitized and increased by La

3+

Gd

3+

and Y

3+

of which Gd

3+

has the strongest effect.But their peak positions did not change obviously.The mixed amount can also affect the fluorescence intensities of the mixed complexes.Take EuLa and ThGd complexes for example

when the molar ratio of Eu and La in the mixed complexes is equal to 0.9:0.1

the fluo-rescence of the complex is the strongest

and the same to TbGd complexes. In a conclusion

La

3+

Gd

3+

and Y

3+

can sensitize and increase the fluorescence intensities of Eu and Tb complexes and do not change the peak positions.Moreover the mixed amount of these non-fluorescence ions can affect the sensitization.