Estudo de nanocompósitos luminescentes baseados em complexos de Eu(III) e Ir(III) ancorados à nanopartículas de sílica por bases de Schiff

• Autor(a) principal: Mutti, Alessandra Mara Garbosa [UNESP]
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/127580
• topic: Química inorgânica; Silica; Nanopartículas

Silica is a versatile material and has specific properties that make it a good host for molecules and biomolecules suggesting promising applications such as in catalysis, drug controlled release, biomarkers, and so on. To be used as a biomarker it requires a luminescent molecule covalently linked to its surface. For this application, lanthanide complexes are very promising since they exhibit intense multicolor emissions. Also, some transition metal complexes exhibit good luminescent properties, that makes them good candidates for use as luminescent probes in biological media. The main scope of this work is the synthesis, characterization and evaluation of luminescent functionalized silica nanoparticles. These new phosphors based on silica nanoparticles were obtained by sol-gel method, followed by covalent bounding with Eu3+-complexes or Ir3+-complexes, through a Schiff base ligand type. We also describe the synthesis and characterization of two Schiff base ligands: Salba and SalpaSi. The last one was attached to the silica nanoparticles surface to form SalpaSi- SiO2. Three complexes {[Eu(salba)3], [Eu(salen)2] and [Ir(ppy)2(salba)]} and three conjugates {[Eu(salpaSi)(H2O)x]-SiO2, [Eu(dbm)3(salpaSi)]-SiO2 and [Ir(ppy)2(salpaSi)]-SiO2} were prepared. All compounds were analyzed by Infrared Spectroscopy, confirming their synthesis. Functionalized silica nanoparticles were analyzed by Scanning Electronic Microscopy, from where we could observe these particles are spheroidal shaped with diameter in the range 200-250 nm. The Eu3+ ion in the complexes was sensitized by the ligands emitting a reddish color, while the use of Ir3+ caused an increase in the emission intensity of the ligand, caused by strong spin-orbital coupling