J. Dexpert-ghys et al., Complexes of rare earths and dipicolinato ions encapsulated in X- and Y-zeolites: Luminescence properties, J INCL P MA, 39(3-4), 2001, pp. 261-267
Citations number
31
Categorie Soggetti
Chemistry
Journal title
JOURNAL OF INCLUSION PHENOMENA AND MACROCYCLIC CHEMISTRY
The complexes {Ln(DP)}Z where Ln(3+) = La3+ or Eu3+, DP is the dipicolinate
ion (2,6)-pyridine dicarboxylate: C5H3N(COO-)(2) and Z = one of the faujas
ite-type X or Y zeolites have been synthesized and investigated by XRD, Ram
an and IR spectroscopy, and Eu3+ luminescence spectroscopy. The rare earth
complexes are synthesized inside the super-cages of the zeolites; the degre
e of complexation never exceeds 1DP/1Ln. Only the Ln ions, which are in the
super-cages, may be complexed. Luminescent europium complexes encapsulated
in zeolite matrices were obtained. The D-5(0) --> F-J luminescence observe
d under excitation into the lowest-energy ligand-centered absorption band (
275 nm) indicates that a DP to Eu energy transfer occurs in these systems.
The complex versus the zeolite framework conformations influence the europi
um emission characteristics: the transfer is more efficient when the comple
xed europium [Eu(DP)](+) is directly bonded to the framework oxygen atoms r
ather than to a residual water molecule.