Síntese de nanocomplexos lantanídicos com ligantes orgânicos mistos - propriedades fotônicas e térmicas.

Abstract

Researches involving lanthanide ions coordination wins space more and more in scientific area, due luminescence properties evidenced in those transition metals. Concomitantly mesoionic compounds wake up attention a lot due be dipolar heterocyclic of nonconventional structures, presenting biological activity very diversified besides being intermediate in cycloaddition reactions, to obtaining new heterocyclic derived. In those terms, that work had as objective synthesizes and characterize nanocomplexes of lanthanide ions: Nd3+, Eu3+ and Er3+ with mesoionic 2-(4-chlorophenyl)-3-methyl-4-(4-methoxyphenyl) 1,3-thiazolium-5-thiolate (IM) and a second bipyridinic bonding (bipy), seeking to increase luminescence and biological properties of nanocomplexes. Starting of reaction between chloride of its respective lanthanide with organic bonding under six hours reflux and temperature of 60 oC, were obtained neodymium, europium and erbium complexes in form of nanopowders. Nanocomplexes were characterized through physical-chemistry, spectrometric, thermoanalytical, structural and morphological analysis. Lanthanidic ions nanocomplexes presented satisfactory results of elementary analysis, for theoretical and experimental values, what confirmed the proposed stoichiometry (1:3:1), besides to corroborate ions chromatography results in what purity of that materials. Bonding coordination with lanthanide ions occurred through exocyclic sulfur atoms (C-S) of mesoionic of 1,3-thiazolium-5-thiolate group and nitrogen atoms (C-N) of 2’2-bipyridine, that can be observed on infrared spectra, by displacements of this bands present on free and coordinate bondings. Sintered complexes presented crystalite size with variation among 42.42nm to 79.05nm, what checks to their nanometric dimensions. Micrographs confirmed agglomerates formation and evidenced crystallinity of structures. Erbium nanocomplex showed more thermal unstable, with mass loss (81.2%), could have its addressed application to drug. Among obtained nanocomplexes europium presented well defined emission spectrum in visible area, characterizing antenna effect which enables its application in light conversion molecular devices (LCMDs).