Characteristics of the Phosphorescence Spectra of Benzophenone Adsorbed on Ti−Al Binary Oxides

Nishiguchi, Hiroyasu; Zhang, † and J.-L.; Anpo, Masakazu

doi:10.1021/la001402n

Cited by 12 publications

(10 citation statements)

References 47 publications

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“…However, we neglected this possibility because (1) relative intensity of (C 7 H 7 ) þ to Tol þ is not enhanced when BP concentration increases (Fig. 1b), (2) [Tol(C 7 H 7 )] þ does not appear when BP concentration is negligibly low (0.03%) while [(BP)H] þ is seen when BP concentration is high (0.4%) in Fig. 1c, and (3) [Tol 3 (C 7 H 7 )] þ ðm=e ¼ 367Þ is not recognized in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Unfortunately, pKa values of protonated carbonyls and alcohols are negative, which makes it difficult to study them in aqueous solution. The protonated species are recognized only in highly acidic media [1], in zeolite [2], and in the gas phase. Ionization of gaseous clusters, being composed of simple molecules such as H 2 O, methanol and acetaldehyde, produces stable protonated clusters [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…In [(BP)2 H] þ , a proton is trapped between two oxygens belonging to the different BPÕs and the BP)2 H] þ consists of [(BP)H] þ and BP moieties connected by a strong hydrogen-bond.We calculated the energies of [(BP)H 3 ] þ isomers at optimized structures by a DFT method with the B3LYP/6-31G(d) level of theory and the energy diagram for some isomers is shown inFig. 4.…”

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confidence: 99%

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Protonation and multi-hydrogenation of benzophenone (BP) in BP/toluene and BP/ethanol binary cation clusters

Kawai

Tanaka

Nakashima

et al. 2003

Chemical Physics Letters

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Protonation and multi-hydrogenation of benzophenone (BP) in BP/toluene and BP/ethanol binary cation clusters

Kawai

Tanaka

Nakashima

et al. 2003

Chemical Physics Letters

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“…Assim, a quantificação luminescente de analitos, como filtros solares orgânicos, ácido p-metocinâmico, 2-etil-metil-p-metoxicinamato 182 e derivados da benzofenona; [183][184][185][186][187][188][189][190][191] substâncias estrogênicas, como os derivados do estradiol; e antiinflamatórios não-esteróides (AINEs) como a indometacina, acetamicina, ibuprofeno, e muitos outros fármacos, será plausível dependendo apenas da habilidade do pesquisador para investigar e/ou explorar novas rotas alternativas que permitam quantificar esses analitos através da espectroscopia de luminescência.…”

Section: Considerações Finais E Conclusõesunclassified

Aplicação e avanços da espectroscopia de luminescência em análises farmacêuticas

et al. 2008

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Recebido em 20/10/06; aceito em 30/11/07; publicado na web em 4/9/08 APPLICATION AND ADVANCES IN THE LUMINESCENCE SPECTROSCOPY IN PHARMACEUTICAL ANALYSES. This paper provides a review on the latest advances and applications of the luminescence spectroscopy for the development of pharmaceuticals analyses methods, basically based on the photo-and chemiluminescence. The different forms of the drugs determination on pharmaceuticals through the fluorescence and chemiluminescence are discussed. The analyses include the drugs native fluorescence (liquid and solid-phases); the fluorescence from the oxidizing or reducing forms of the drug; the fluorescence from the chemical derivatization and their photochemistry and hydrolysis reactions. The quenching of luminescence and chemiluminescence generation for the pharmaceutical quantification are also shown. Finally, the trends and future perspectives of the luminescence spectroscopy in the field of the pharmaceutical research are discussed.Keywords: luminescence spectroscopy; drugs; cosmetics analysis; introdução Devido ao progresso contínuo em técnicas e instrumentos, a indústria farmacêutica busca o emprego de metodologias que ofereçam maior sensibilidade, seletividade, robustez, precisão, exatidão e rapidez. Neste sentido, um grande número de equipamentos de cromatografia líquida de alta eficiência (CLAE) com diversos tipos de detecção domina este ramo industrial. Contudo, o advento da sofisticação de instrumentação automatizada de espectrômetros de luminescência poderá resultar em um substancial aumento de aplicações desta técnica instrumental na indústria farmacêutica, principalmente, no que se refere à análise diretamente na matriz do medicamento.A espectroscopia de luminescência é uma ferramenta analítica extremamente sensível e tem sido amplamente aplicada na resolução de problemas que requerem baixos limites de detecção, podendo ser facilmente encontrados na literatura muitos trabalhos mostrando análises ao nível de traços.1-6 A sensibilidade inerente a esta técnica é consideravelmente maior em comparação a outras metodologias, entre elas a espectrofotometria UV/visível, apresentando limites de detecção de até três ordens de grandeza menores, os quais normalmente se encontram na faixa de ng mL -1 , sendo conseqüência do baixo sinal de fundo que as medidas fluorescentes apresentam. Diferentemente do que ocorre no fenômeno da luminescência, nas medidas de absorbância o sinal está associado à atenuação da intensidade de um feixe de radiação por uma espécie absorvente. Nos casos onde a quantidade da espécie é pequena, esta atenuação é menor, tornando assim a detecção da espécie difícil. Outra característica importante da luminescência diz respeito à seletividade, porque espécies com rendimentos quânticos de fluorescência apreciáveis são menos comuns do que substâncias cuja fluorescência não pode ser detectada. Desta forma, moléculas fluorescentes apresentam comprimento de onda característico de excitação e/ou emissão. Adicionalmente, o comprimento de onda de excitação d...

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“…The photophysics and photochemistry of molecules at liquid/solid interfaces are important in many areas of science including heterogeneous photocatalysis, environmental photochemistry and photobinding and photocuring processes used to modify the interfacial properties of materials. Several publications investigated the effect of the surface nature on the photophysics and photochemistry of adsorbed molecules (7–10). The photophysics and photochemistry of adsorbed molecules differ from that of molecules in the gas phase and in solution.…”

Section: Introductionmentioning

confidence: 99%

Generation of Chemisorbed Benzyl Radicals on Silica Nanoparticles

Arce

Rosso

Oliveira

et al. 2010

Photochem & Photobiology

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Functionalized silica nanoparticles (NP) were obtained by esterification of the silanol groups of fumed silica nanoparticles with benzyl alcohol. These particles were characterized by Fourier transform infrared spectroscopy, (13)C and (29)Si NMR spectroscopy, thermogravimetry, total organic carbon, Brunauer-Emmett-Teller analysis, UV-visible spectroscopy, and transmission electron microscopy. NP suspensions in water/acetonitrile mixtures were used as quenchers of benzophenone (BP) phosphorescence in time-resolved experiments at the excitation wavelength of 266 nm. The phosphorescence signals obtained in the presence of the nanoparticles were fitted to biexponential decays. Both decays were accelerated in the presence of increasing amounts of NP. A model, including the reversible adsorption of BP on the NP, which was supported by computer simulations accounts for the observed results. Laser flash-photolysis experiments with excitation at 266 nm of NP suspensions in water/acetonitrile in the presence of BP generated benzyl radicals that were attached to the silica surface. These radicals were detected at their absorption maxima (320 nm) by transient optical techniques.

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Characteristics of the Phosphorescence Spectra of Benzophenone Adsorbed on Ti−Al Binary Oxides

Cited by 12 publications

References 47 publications

Protonation and multi-hydrogenation of benzophenone (BP) in BP/toluene and BP/ethanol binary cation clusters

Protonation and multi-hydrogenation of benzophenone (BP) in BP/toluene and BP/ethanol binary cation clusters

Aplicação e avanços da espectroscopia de luminescência em análises farmacêuticas

Generation of Chemisorbed Benzyl Radicals on Silica Nanoparticles

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