Detalhes bibliográficos
Ano de defesa: |
2015 |
Autor(a) principal: |
Khalid, Muhammad |
Orientador(a): |
Não Informado pela instituição |
Banca de defesa: |
Não Informado pela instituição |
Tipo de documento: |
Tese
|
Tipo de acesso: |
Acesso aberto |
Idioma: |
eng |
Instituição de defesa: |
Biblioteca Digitais de Teses e Dissertações da USP
|
Programa de Pós-Graduação: |
Não Informado pela instituição
|
Departamento: |
Não Informado pela instituição
|
País: |
Não Informado pela instituição
|
Palavras-chave em Português: |
|
Link de acesso: |
http://www.teses.usp.br/teses/disponiveis/46/46136/tde-29092015-114251/
|
Resumo: |
The cyclic peroxides: diphenoyl peroxide (1), spiro-adamantyl-1,2-dioxetanone (2) and 4-(3-tert-butyldimethylsilyloxyphenyl)-4-methoxyspiro[1.2-dioxetane-3.2\'-adamantane] (3) synthesized, purified and characterized, also their kinetic and chemiluminescence (CL) properties were determined. The influence of solvent polarity on the chemiexcitation parameters of the catalyzed decomposition of 1 and 2, as well as the induced decomposition of 3 were examined in several binary solvent mixtures with different polarity and polarizability parameters, but similar viscosities. For solvents with low polarity, singlet quantum yields for the intermolecular catalyzed decomposition of diphenoyl peroxide (1,) and 1,2-dioxetanone (2) increase in function of medium polarity, showing maximum values in mediums of intermediate polarity, and decreasing in highly polar mixtures. For the induced decomposition of 3, the quantum yield showed to increase with increasing solvent polarity, including high polar solvent systems. In the binary solvent systems studied, the polarizability parameter showed to be contrary to the polarity values, therefore, it might appear that an increase of polarizability leads to a decrease in the singlet quantum yields for catalyzed decomposition of diphenoyl peroxide (1) and the induced decomposition of 3, however an increase in the singlet quantum yields for 1,2-dioxetanone 2. The three CL systems were also studied in binary solvent mixtures with different viscosities but similar polarity and polarizability parameters and singlet quantum yields showed an increase with increasing medium viscosity. Data were analyzed by using the collisional and the free volume models. The highly efficient intramolecular system induced 1,2-dioxetane 3 decomposition showed to be much more sensible to viscosity effects than the inefficient intermolecular systems. This surprising fact indicates that, even showing a significant solvent-cage effect, the induced 1,2-dioxetane should occur by an intramolecular electron back transfer. Moreover, chemiluminescence parameters of these systems were studied in several pure solvents. The obtained singlet quantum yields were correlated with viscosity, polarizability and polarity parameters by using multiple linear regression analysis. |