Molecular recognition at the electrode-solution interface. Design, self-assembly, and interfacial binding properties of a molecular sensor

Rojas, Maria T.; Kaifer, Ángel E.

doi:10.1021/ja00126a041

Cited by 85 publications

(53 citation statements)

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“…188 The formal potential of a cyclic bis(bipyridinium) molecule in a SAM shifts in the negative direction in the presence of indole or catechol. 189 A bis(acetylacetone)sulfide forms SAMs that bind Cu 2C , Pb 2C and Zn 2C selectively in the presence of Fe 2C or Fe 3C . 190 -192 The first three ions readily form four-coordinate complexes, while iron cations prefers a six-coordinate geometry.…”

Section: Preconcentration and Selective Bindingmentioning

confidence: 99%

Self‐Assembled Monolayers on Electrodes

Finklea

2000

Encyclopedia of Analytical Chemistry

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Alkanethiols and related molecules spontaneously adsorb from solution or vapor phase onto oxide‐free metals, especially gold, to form close‐packed oriented monolayers. The ease and flexibility of the self‐assembly process provides a convenient method for altering the properties of the metal as an electrode. The close‐packed hydrocarbon layer blocks access of most solution species to the electrode surface. Consequently, interfacial capacitances are markedly reduced and most electron‐transfer reactions are strongly inhibited. The monolayers also provide a foundation for attachment of additional molecules or molecular layers to electrodes. Self‐assembled monolayers (SAMs) on electrodes have been used in voltammetric methods to improve the analytical sensitivity and to impart greater selectivity towards specific analytes. Redox molecules have been anchored at fixed and controllable distances from the electrode surface, thereby permitting the study of electron‐transfer kinetics over long distances and at large driving forces. The ability of SAMs to inhibit metal corrosion and to promote better adhesion of electroactive polymers has been demonstrated.

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Section: Preconcentration and Selective Bindingmentioning

confidence: 99%

Self‐Assembled Monolayers on Electrodes

Finklea

2000

Encyclopedia of Analytical Chemistry

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“…O grupo terminal de enxofre destas moléculas é ligado ao ouro via uma ligação S-Au extremamente forte, enquanto que os grupos funcionais na outra extremidade da molécula controlam as propriedades da superfície do eletrodo, tais grupos podem ser manipulados de acordo com as mais variadas aplicações [54][55][56][57][58] . A SAM mais estudada e compreendida é a que emprega alcanotióis (CH 3 (CH 2 ) n S -) sobre superfícies de Au (111).…”

Section: Introductionunclassified

Emprego de monocamadas auto-organizadas no desenvolvimento de sensores eletroquímicos

Freire¹,

Pessôa²,

Kubota³

2003

Quím. Nova

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Recebido em 18/7/02; aceito 9/10/02 SELF-ASSEMBLED MONOLAYERS APPLICATIONS FOR THE DEVELOPMENT OF ELECTROCHEMICAL SENSORS. Selfassembled monolayers (SAMs) modified electrodes exhibit unique behavior that can greatly benefit electrochemical sensing. This brief review highlights the applications of SAM modified electrodes in electroanalytical chemistry. After a general introduction, which includes the approaches for SAM development, different electrochemical systems for detecting inorganic and organic species are described and discussed. Special attention to the coupling of biological sensing element to the SAM is given, which can selectively recognize the analyte. Future prospects are also evaluated.Keywords: chemically modified electrodes; self-assembled monolayers; electrochemical sensors. INTRODUÇÃOO desenvolvimento de sensores eletroquímicos é uma das áreas de maior e mais rápido crescimento dentro da Química Analítica, principalmente devido aos novos desafios impostos por amostras de interesse industrial, clínico e ambiental, que têm levado a uma crescente busca por sensores com melhores características, tais como alta sensibilidade, seletividade e estabilidade [1][2][3][4][5][6][7][8] . Apesar da grande versatilidade e perspectivas apresentadas pelos sensores eletroquímicos, a utilidade de um eletrodo é muitas vezes limitada devido a uma passivação gradual de sua superfície, que é conseqüência principalmente da adsorção dos produtos da própria reação de óxido-redução utilizada na detecção, ou ainda, dos sub-produtos destas reações que podem se polimerizar e se depositar sobre a superfície dos eletrodos 6 . Além disso, a sensibilidade de muitos analitos importantes pode ser prejudicada em função da cinética de transferência de elétrons entre estes compostos e os materiais dos eletrodos ser excessivamente lenta 9 . Uma outra limitação é a dificuldade de discriminar entre compostos alvos que possuam características redox similares 9 . Uma área que oferece grande potencial para minimizar os problemas acima descritos, e conseqüentemente para aumentar a aplicabilidade e eficiência dos sensores eletroquímicos, é a que compreende os chamados eletrodos quimicamente modificados (EQM) 9,10 . A habilidade para controlar e manipular deliberadamente as propriedades das superfícies dos eletrodos pode proporcionar uma variedade de efeitos atrativos, levando a superfícies com características que podem contornar efetivamente muitos dos problemas apresentados pelos sensores eletroquímicos tradicionais.Estudos experimentais, suportados pela teoria, têm mostrado que a velocidade de transferência de elétrons pode ser sensivelmente afetada em função da modificação da superfície dos eletrodos 11. A classificação das reações do eletrodo pode ser feita com base no grau de interação entre os reagentes e a superfície do eletrodo, ocorrida durante o estado de transição da transferência de elétrons 12 . Os processos de transferência de elétrons onde as interações entre as espécies reagentes e a superfície do eletrodo são fracas e não es...

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“…Another point of interest in the context of this study is that disulfide bridges are known to react cleanly with gold surfaces and open to give rise to two AuÀS bonds. [45][46][47][48][49][50][51][52][53][54] The grafting of the thiol-functionalized cluster 1 by selfassembly was then performed on a AuA C H T U N G T R E N N U N G (111) surface. It is important to emphasize that the clusters exhibit diamagnetic behavior at this stage.…”

Section: Resultsmentioning

confidence: 99%

“…Preliminary results of XAS investigations on synchrotron starting from 2 are identical to those with 1, which is consistent with the breaking of the disulfide linkage to give two Au À S bonds. [45][46][47][48][49][50][51][52][53][54] This finding appears to be promising since the former precursor is easier to prepare and is more stable than 1. Future investigations will focus on the use of 2 and on more detailed comparisons between these precursors.…”

Section: Wwwchemeurjorgmentioning

confidence: 96%

Grafting and Thermal Stripping of Organo‐Bimetallic Clusters on Au Surfaces: Toward Controlled Co/Ru Aggregates

Naitabdi

Toulemonde

Bucher

et al. 2008

Chemistry A European J

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The controlled stoichiometry of heterometallic carbonyl clusters make them attractive precursors for the stabilization of bare metal alloy clusters for magnetic applications. The mixed-metal molecular cluster [RuCo3(H)(CO)12] has been functionalized with the phosphane-thiol ligand Ph2PCH2CH2SH to allow subsequent anchoring on a gold surface. The resulting tetrahedral cluster [RuCo3(H)(CO)11(Ph2PCH2CH2SH)] (1) has been characterized by X-ray diffraction and the P-monodentate ligand is axially bound to a cobalt center and trans to the ruthenium cap. This synthesis also yielded the product of oxidative coupling, in which two SH groups were coupled intermolecularly to give a disulfide ligand that links two tetrahedral cluster units in [{RuCo3(H)(CO)11(Ph2PCH2CH2S)}2] (2). This cluster has also been characterized by X-ray diffractions studies. After deposition of 1 on a Au(111) surface by self-assembly, the carbonyl ligands were stripped off by thermal annealing in ultra-high vacuum (UHV) to form a metallic species. X-ray photoelectron spectroscopic measurements performed as a function of the annealing temperature show that the cobalt and ruthenium centers converge towards metallic character and that the stoichiometry of the alloy is retained during the annealing process. Preliminary X-ray absorption spectroscopy (XAS) synchrotron experiments indicate that clusters 1 and 2 behave similarly, which is consistent with the retention of their tetrahedral units on the gold surface after transformation of the thiol function or breaking of the disulfide bond to form Au--S bonds, respectively, has occurred.

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Molecular recognition at the electrode-solution interface. Design, self-assembly, and interfacial binding properties of a molecular sensor

Cited by 85 publications

References 1 publication

Self‐Assembled Monolayers on Electrodes

Self‐Assembled Monolayers on Electrodes

Emprego de monocamadas auto-organizadas no desenvolvimento de sensores eletroquímicos

Grafting and Thermal Stripping of Organo‐Bimetallic Clusters on Au Surfaces: Toward Controlled Co/Ru Aggregates

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