The luminescence properties of rare earth complexes with

m

-methylbenzoic acid REL

3

(RE=Eu

Tb; HL=

m

-CH

3

C

6

H

4

CO

2

H) and with o-chlorobenzoic acid REL

3

H

2

O RE=Eu

Tb; HL=

o

-ClC

6

H

4

CO

2

H) are reported in this paper. The influence of the coordination environment on energy transfer; the luminescence intensity and life time has been discussed.For Tb ions when the ligand in the complexes is changed

the position of the maximum of the excitation wavelength is displaced lightly

the emission of Tb-

mm

is much stronger than that of Tb--Cl

and Tb-

mm

has a longer decay. The luminescence phenomenon of Eu-

mm

and Eu-Cl

however

is contrary

both Eu-

mm

and Eu-Cl showstronger

5

D

0

→

7

F

2

transition of Eu

3+

but Eu-Cl has a stronger emission intensity and longer lifetime. The reason for these results is believed to be due to the coordination environment of the complexes.Although there exist O-H bonds with high vibrational energy in Eu-Cl

the formation of hydrogen bonds may reduce the vibrational energy by increasing the rigidity of the complex. So the energy transmission can occur efficiently from ligand to Eu

3+

and the emission of Eu-Cl is stronger than that of Eu-

mm

. The deactivation via vibronic coupling is

however

less efficient for Tb

3+

and the emission of Tb-

mm

is stronger than that of Tb-Cl.