Novel lanthanide luminescent materials based on complexes of 3-hydroxypicolinic acid and silica nanoparticles

Soares-Santos, P.C.R., Nogueira, H.I.S., Felix, V., Drew, M.G.B., Ferreira, R.A.S., Carlos, L.D. and Trindade, T. (2003) Novel lanthanide luminescent materials based on complexes of 3-hydroxypicolinic acid and silica nanoparticles. Chemistry of Materials, 15 (1). pp. 100-108. ISSN 0897-4756 doi: 10.1021/cm021188j

Abstract/Summary

New lanthanide complexes of 3-hydroxypicolinic acid (HpicOH) were prepared: [Ln(H2O)(picOH)(2)(mu-HpicO)].3H(2)O (Ln = Eu, Tb, Er). The complexes were characterized using photoluminescence, infrared, Raman, and H-1 NMR spectroscopy, and elemental analysis. The crystal structure of [Eu(H2O)(picOH)(2)(mu-HpicO)] . 3H(2)O 1 was determined by X-ray diffraction. Compound 1 crystallizes in a monoclinic system with space group P2(1)/c and cell parameters a = 9.105(13) Angstrom, b = 18.796(25) Angstrom, and c = 13.531(17) Angstrom, and beta = 104.86(1) deg. The 3-hydroxypicolinate ligands coordinate through both N,O- or O,O- chelation to the lanthanide ions, as shown by X-ray and spectroscopic results. Photoluminescence measurements were performed for the Eu(III) and Tb(III) complexes; the Eu(III) complex was investigated in more detail. The Eu(III) compound is highly luminescent and acts as a photoactive center in nanocomposite materials whose host matrixes are silica nanoparticles.