resumo
New lanthanide complexes of 3-hydroxypicolinic acid (HpicOH) were prepared: [Ln(H(2)O)(picOH)(2)(mu-HpicO)].3H(2)O (Ln = Eu, Tb, Er). The complexes were characterized using photoluminescence, infrared, Raman, and (1)H NMR spectroscopy, and elemental analysis. The crystal structure of [Eu(H(2)O)(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.
palavras-chave
SPECTROSCOPIC PROPERTIES; CRYSTAL-STRUCTURES; METAL-COMPLEXES; TRANSITION; EUROPIUM(III); NANOCRYSTALS; PARAMETERS; EMISSION; 2ND-ROW; TERBIUM
categoria
Chemistry; Materials Science
autores
Soares-Santos, PCR; Nogueira, HIS; Felix, V; Drew, MGB; Ferreira, RAS; Carlos, LD; Trindade, T
nossos autores
Helena Isabel Seguro Nogueira
Professor Auxiliar com Agregação
Luís Carlos
Professor Catedrático
Maria Rute de Amorim e Sá Ferreira André
Professor Catedrático
Paula Cristina Ramos Soares e Santos
Técnico de Laboratório
Tito Trindade
Professor Catedrático