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BIBTEX RIS

5-(4-pyridinyl)-1,3,4-oxadiazole-2-thiol on gold: SAM Formation and electroactivity

2008; Brazilian Chemical Society; Volume: 19; Issue: 4 Linguagem: Inglês

10.1590/s0103-50532008000400015

ISSN

1678-4790

Autores

Tércio de F. Paulo, Maria A. S. da Silva, Solange de Oliveira Pinheiro, Emerson Meyer, Lucidalva S. Pinheiro, J. A. K. Freire, Auro Atsushi Tanaka, Pedro de Lima‐Neto, Ícaro de Sousa Moreira, Izaura C.N. Diógenes,

Tópico(s)

Conducting polymers and applications

Resumo

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 DHads and DGads 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 × 10-3 cm s-1.

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