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http://repositorio.ufc.br/handle/riufc/72343| Type: | Artigo de Periódico |
| Title: | 5-(4-pyridinyl)-1,3,4-oxadiazole-2-thiol on gold: SAM Formation and electroactivity |
| Authors: | Paulo, Tércio de Freitas Silva, Maria Aparecida Santiago da Pinheiro, Solange de Oliveira Meyer, Emerson Pinheiro, Lucidalva dos Santos Freire, José Alexander de King Tanaka, Auro Atsushi Lima Neto, Pedro de Moreira, Ícaro de Souza Diógenes, Izaura Cirino Nogueira |
| Keywords: | Oxadiazole;Thiol;SAMs;STM;Kinetic of adsorption;Cyt c;Oxadiazol;Cinética de adsorção |
| Issue Date: | 2008 |
| Publisher: | Journal of the Brazilian Chemical Society |
| Citation: | PAULO, Tércio de Freitas; SILVA, Maria Aparecida Santiago da; PINHEIRO, Solange de Oliveira; MEYER, Emerson; PINHEIRO, Lucidalva dos Santos; FREIRE, José Alexander de King; TANAKA, Auro Atsushi; LIMA NETO, Pedro de; MOREIRA, Ícaro de Souza; DIÓGENES, Izaura Cirino Nogueira. 5-(4-pyridinyl)-1,3,4-oxadiazole-2-thiol on gold: SAM Formation and electroactivity. Journal of the Brazilian Chemical Society. [s.l.], v.19, n. 4, p. 711-719, 2008 |
| Abstract in Brazilian Portuguese: | O composto 5-(4-pyridinyl)-1,3,4-oxadiazole-2-thiol (Hpyt) adsorve espontaneamente sobre ouro formando SAMs (“Self-Assembled Monolayers”) que, de acordo com os resultados eletroquímicos e de STM (“Scanning Tunneling Microscopy”), contêm poros através dos quais as moléculas dos complexos [Fe(CN)6] 4– e [Ru(NH3 )6 ]3+ acessam a superfície livre de modificação. Para o complexo [Fe(CN)6 ]4, a dependência da corrente faradáica com o pH da solução eletrolítica permitiu o cálculo do pKa da molécula de Hpyt adsorvida sobre ouro (4,2). Os parâmetros termodinâmicos, ΔH ads and ΔG ads , para o processo de adsorção desta molécula foram estimados em –20,01 e –39,39 kJ mol-1 , respectivamente, utilizando-se o modelo de Langmuir. O processo redox da metaloproteína citocromo c foi estudado utilizando-se a SAM de Hpyt. A constante de velocidade heterogênea de transferência de elétrons foi calculada em 2,29 r 10 –3 cm s -1 . |
| Abstract: | 5-(4-pyridinyl)-1,3,4-oxadiazole-2-thiol (Hpyt) spontaneously adsorbs on gold forming SAMs (self-assembled monolayers) that, based on STM (Scanning Tunneling Microscopy) and electrochemical data, contain pinholes through which [Fe(CN)6 ]4– and [Ru(NH3 )6 ]3+ probe molecules access the underlying gold electrode. For the former molecule, the dependence of the faradaic current on the electrolyte solution pH value allowed the evaluation of the surface pKa as 4.2. The thermodynamic parameters ΔHads and ΔGads for the Hpyt adsorption process could be described by the Langmuir model and were calculated as –20.01 and –39.39 kJ mol -1, respectively. Electrodic redox reaction of cytochrome c metalloprotein was accessed by using the Hpyt SAM with a heterogeneous electron transfer rate constant of 2.29 r 10–3 cm s -1 . |
| URI: | http://www.repositorio.ufc.br/handle/riufc/72343 |
| ISSN: | 1678-4790 |
| Appears in Collections: | DEME - Artigos publicados em revista científica |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 2008_art_plimaneto.pdf | 407,76 kB | Adobe PDF | View/Open |
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