60 research outputs found
Novel luminescent materials based on silica doped with an europium(III) complex of 2,6-dihydroxybenzoic acid: the crystal structure of [(nBu4N)2[Eu(2,6-Hdhb)(5)(H2O)(2)]
Novel luminescent materials were prepared by introducing a new Eu3+ complex of 2,6-dihydroxybenzoic acid (2,6-H2dhb) into a silica
gel made by the sol–gel method. The crystal structure of the resulting complex [nBu4N]2[Eu(2,6-Hdhb)5(H2O)2] was determined using
single-crystal X-ray diffraction. The compound was further characterised using FTIR, FT-Raman and elemental analysis. Photoluminescence
measurements were performed for the isolated Eu(III) 2,6-dihydroxybenzoate complex and also for the related silica composite material
Spectroscopic studies of Ln(III) complexes with polyoxometalates in solids, and aqueous and non-aqueous solutions
Chosen polyoxometalate (POM) anions and their lanthanide(III) complexes, LnPOM, have
been synthesized and spectroscopically characterized in solid state, aqueous and non-aqueous solutions.
POMs, such as Keggin's, Dawson's and Anderson's type, Na9EuW10O36, compositions that function as inorganic cryptands ([(Na)P5W30O110]14−-Preyssler anion, and [(Na)As4W40O140]27−), containing inorganic (Na+,K+,NH4+) or organic (tetrabutylammonium, NBu4+) counter cations were obtained and their Ln(III) complexes
(sandwiched and encapsulated) studied. The synthesized compounds were identified using elemental
and thermogravimetric analysis, UV-Vis spectrophotometry and FTIR spectroscopy. The complexation studies
were carried out with the use Nd(III) and Er(III) optical absorption and Eu(III) luminescence spectroscopy.
Luminescence characterization, including results of intensity, quantum yields and luminescence lifetimes of
EuPOM complexes in aqueous, non-aqueous solutions (DMF, DMSO, acetonitryle) and solid are discussed.
Based on luminescence lifetime measurements of the Eu(III) ion the hydration numbers of its sandwiched
(efficient emitters) and encrypted complexes have been determined and quenching effect discussed. The
Eu(III) complexes entrapped in a xerogel matrix have been studied as luminescent materials. Luminescence
intensity, lifetime and quantum yield of the EuPOM materials and their photochemical stability, during continuous
UV irradiation, were tested
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