Banca de DEFESA: RENATA FLÁVIA FERRAZ DO NASCIMENTO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : RENATA FLÁVIA FERRAZ DO NASCIMENTO
DATE: 03/06/2022
TIME: 09:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

DEVELOPMENT OF A MESOPOROUS PHOTOCHROMIC MATERIAL DERIVED FROM HYDROXY-FUNCTIONAL SPIROPYRAN MOLECULES 

KEY WORDS:

Photochromic molecules, MCM-48, Hybrid Materials.

PAGES: 87
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

The present work documents the synthesis and structural characterization of hydroxy-functional spiropyran-type molecules, for use in the formation of complexes with metal ions of different elements of the periodic table, s-block (Ca) and d-block (Fe, Ni ), in order to investigate the stability of the merocyanine isomer and also the use of these molecules in the development of a photochromic material supported on mesoporous silica of the MCM-48 type. In this research, spiropyran molecules were synthesized from the condensation reaction of methyleneinoline precursors and hydroxybenzaldehyde derivatives, from the adaptation of methodologies already existing in the literature. The structures of spiropyrans were confirmed using UV-Vis, Infrared and 1H NMR spectrometric techniques. With the UV-Vis technique, it was possible to evaluate the differences in the absorptions between the spiropyran and merocyanine isomers of the synthesized molecules, as well as to investigate the photochromism. With the techniques of infrared spectroscopy and 1H NMR, it was possible to analyze the structures of spiropyrans. In addition to the characterization techniques mentioned above, the photochromic mesoporous material was characterized by thermogravimetric analysis and scanning electron microscopy images. As a result, the use of spiropyran supported on MCM-48 presented optical characteristics similar to those of pure compounds, demonstrating that the adapted methodology was adequate for the development of this type of material, as it allowed its incorporation without changes in the molecules/structures. The hydroxyls present in spiropyran allowed its association by covalent bonds to the compound MCM-48 and from that, it was observed that this incorporation did not change the morphology of MCM-48, however, it increased its thermal stability and a material was obtained that responds to the action of the light stimulus, thus realizing positive photochromism. This photochromic response combined with the properties of MCM-48 make them good candidates to be applied in areas of constant rise, for example, in the controlled delivery of drugs activated by light.

BANKING MEMBERS:
Interno - 2457389 - EDUARDO PADRON HERNANDEZ
Interna - 2163324 - JOANNA ELZBIETA KULESZA
Externo à Instituição - MARCOS VINICIUS DA SILVA PAULA - UFPA
Externo à Instituição - RODRIGO DA SILVA VIANA - UFPE
Presidente - 1354207 - SEVERINO ALVES JUNIOR