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

Journal of the Brazilian Chemical Society

Universidade Federal do Maranhão, São Luís, Brazil¹  Meyer, Emerson¹  Diógenes, Izaura C. N.¹  Pinheiro, Solange de O.¹  Lima Neto, Pedro de¹  Pinheiro, Lucidalva S.¹  Universidade Federal do Ceará, Fortaleza, Brazil¹  Paulo, Tercio de F.¹  Silva, Maria A. S. da¹  Freire, José A.¹  Moreira, Ícaro de S.¹  Tanaka, Auro A.¹ 

关键词: oxadiazole;    thiol;    SAMs;    STM;    kinetic of adsorption;    Cyt c;   

DOI  :  10.1590/S0103-50532008000400015

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

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.

【 授权许可】

Unknown