Investigação do efeito de grupos periféricos de rutênio sobre as propriedades fotofísicas de porfirinas

AUTOR(ES)

Renato Neiva Sampaio

DATA DE PUBLICAÇÃO

2011

RESUMO

In the last few years the search for new organometallic complexes that exhibit large and fast optical responses at UV-Vis and near IR spectrum regions have attracted a considerable interest because of their potential application in devices such as sensors, optical limiters, switches and in medicine, being used as sensitive drugs in photodynamic treatments. Among the metallo-organic materials, porphyrin complexes have deserved a significant attention, especially because of their relatively easy structural manipulation that can be used to tune their photophysical characteristic aiming specific applications. For instance, optical properties of porphyrin molecules are highly sensitive to changes in the central ion and in the outlying substituent. In order to estimate the prospect of this class of materials for the huge amount of possible applications, a complete characterization of the excited state dynamics is imperative. This work concerns about the optical characterization of new type of porphyrins, aiming the understanding of the factors that influence their photo-physical properties. The porphyrins have a wide range of applications which can be manipulated due its structural versatility, such as applications in optical limiting and phototherapy dynamic for cancer. In this way, we propose to combine the porphyrin rings with peripheral ruthenium groups. These, been charge acceptor groups bind to the porphyrin molecules, leading to changes in photo-physical properties. The objective is to analyze these changes via spectroscopic characterization trying to identify intrinsic properties of the molecule, as lifetime of the electronic levels, absorption cross section, fluorescence quantum yields and oscillator strength. In order to obtain these parameters was employed Z-Scan technique, Laser Flashphotolysis, fluorescence and absorption spectroscopy and time resolved fluorescence. The employed techniques provided results that associate spectral changes such as absorption and emission of the porphyrins complexes due ruthenium groups adding, showing improvements in the absorption process and a fluorescence suppression, most probably associated to energy loss by nonradioactive decays.

ASSUNTO(S)

espectroscopia macromoléculas Ótica não-linear fisica

Documentos Relacionados

• Efeito do ultrassom terapêutico sobre as propriedades mecânicas do gastrocnêmio em ratos
• Caracterização de complexos supramoleculares de meso(fenilpiridil)porfirinas e suas propriedades fotofísicas e fotoquímicas
• Efeito de aditivos minerais sobre as propriedades de chapas cimento-madeira
• Efeito das condições de preparação sobre as propriedades do óxido de zircônio sulfatado contendo ferro.
• Efeito do envelhecimento acelerado sobre as propriedades de microconcreto reforçado com fibras longas de sisal