XAFS studies of Tb or Eu cored dendrimer complexes with various properties of luminescence

We studied the extended X-ray absorption fine structure (EXAFS) of Tb or Eu L3-edge of Tb(III) or Eu(III)-cored complexes of different luminescence to which different poly(benzyl ether) dendrons coordinated. The complexes were prepared via a ligand exchange reaction of dendritic carboxylic acid and acetate. Results show that (a) the Eu complex of the first generation of the 3,4- or 3,5-dibenzyloxyphenyl type had a coordination structure different from that of the 2,4-dibenzyloxyphenyl type; (b) the Eu complex of the first generation of 3,5-dinaphthylmethoxyphenyl type had a Eu-O coordination number higher than the total number of oxygen atoms in the carboxylate groups; (c) the Tb complex of the bulky fourth generation had a Th-O coordination number higher than that of the first generation. These results show that the different poly(benzyl ether) dendrons cause the different coordination, which might differently influence the luminescence properties of the complexes.