Supported Monolayers Containing Preformed Binding Sites. Synthesis and Interfacial Binding Properties of a Thiolated .beta.-Cyclodextrin Derivative

Rojas, Maria T.; Koeniger, Rainer; Stoddart, J. Fraser; Kaifer, Ángel E.

doi:10.1021/ja00106a036

Cited by 436 publications

(461 citation statements)

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“…Compounds 1a-1d were directly synthesized in high yield by reacting the corresponding bis-alcohols with thioctic acid in the presence of 1,3-dicyclohexylcarbodiimide (DCC) and 4-(dimethylamino) pyridine (DMAP), using CH 2 Cl 2 as solvent (10)(11)(12)(13)(14)(15)(16)(17)(18). The corresponding crown-annelated TTF bis-alcohol precursors were prepared in reasonable yields following a modification of the literature procedures (28,29,46).…”

Section: Resultsmentioning

confidence: 99%

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Metal ion recognition and molecular templating in self-assembled monolayers of cyclic and acyclic polyethers

Herranz

Colonna

Echegoyen

2002

Proc. Natl. Acad. Sci. U.S.A.

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Our recent work with cyclic and acyclic polyether self-assembled monolayers (SAMs) on gold is presented. A series of dithia-crowntetrathiafulvalene derivatives with one or two disulfide groups has been prepared, and their SAMs on gold have been characterized by electrochemistry and by reflection-absorption infrared spectroscopy. These SAMs are extremely stable on repeated electrochemical potential scans and can selectively recognize alkali metal ions. Acyclic polyether derivatives can also self-assemble on gold to yield selective metal ion recognition domains. Impedance spectroscopy data for these SAMs fit the Langmuir isotherm and allow the determination of ion association constants. Some of the SAMs prepared with new acyclic polyether derivatives are able to detect potassium cations selectively when templated in their presence. These structures are believed to be a consequence of ion ''imprinting'' during the process of SAM formation.T he easy preparation, stability, and versatility of self-assembled monolayers (SAMs) has resulted in considerable activity in this field since the first publication by Nuzzo and Allara (1). Molecular recognition is especially relevant on surfaces because it allows the control of the exchange of signals, structures, and energy through the interfaces (2-4). SAMs allow the introduction of functional groups in the adsorbates, thus offering a powerful way to develop systems that have applications as sensors, devices, and switches (5). Some recent articles have reported surface structures with hydrophobic and hydrophilic properties arranged in nano-strips and honeycomb or homogeneous structures (6), whereas others have detected photo and electrochemical conversion of cis to trans forms within the SAM (7). Other examples have shown the formation of chiral imprinted sites (8). SAM structures have also been prepared for the recognition and sensing of metal ions (9), some of which are electrochemically active (10-18).Relatively recently, and Bryce et al. (23,24) reported, almost simultaneously, the incorporation of crownether groups into SAMs and their use as potential metal ion sensors. The Reinhoudt group used electrochemical impedance spectroscopy (EIS) for SAM characterization and to study the ion recognition processes (19)(20)(21)(22). This technique enables the detection of interfacial ion recognition phenomena when both guest ion and host monolayer are electrochemically inactive, by detecting changes of the charge-transfer resistance induced by metal ion binding (see Fig. 1a; refs. 25 and 26). The report by Bryce et al. (23,24) described SAMs of crown-annelated tetrathiafulvalene (TTF) derivatives, which showed, by cyclic voltammetry (CV), a redox potential shift of the electroactive, surface-confined, crown-TTF group on ion complexation (23, 24). The first TTF-crown SAMs reported by this group were apparently unstable after several electrochemical scans (23). However, in a subsequent report they demonstrated that the stability and electrochemical behavior of the SAMs can be improv...

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Section: Resultsmentioning

confidence: 99%

“…Other examples have shown the formation of chiral imprinted sites (8). SAM structures have also been prepared for the recognition and sensing of metal ions (9), some of which are electrochemically active (10)(11)(12)(13)(14)(15)(16)(17)(18).…”

mentioning

confidence: 99%

Metal ion recognition and molecular templating in self-assembled monolayers of cyclic and acyclic polyethers

Herranz

Colonna

Echegoyen

2002

Proc. Natl. Acad. Sci. U.S.A.

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“…β-Cyclodextrin (β-CD, CP, recrystallized twice from deionized water) and azodiisobutyronitrile (AIBN, CP, recrystallized from ethanol before use) were supplied by Sinopharm Chemical Reagent Co. Per-7-thio-β-cyclodextrin was prepared according to the literature. 37,38 Modified CdS quantum dots (β-CD@QD) was prepared by following reported procedure. 31 Unless specially mentioned, all other chemicals were used as received.…”

Section: Methodsmentioning

confidence: 99%

Dual Stimuli-Responsive Supramolecular Hydrogel Based on Hybrid Inclusion Complex (HIC)

et al. 2010

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A novel dual-responsive supramolecular hydrogel composed of an azobenzene (AZO) endfunctionalized block copolymer PDMA-b-PNIPAM (AZO-(PDMA-b-PNIPAM)) and β-cyclodextrin-modified CdS quantum dot (β-CD@QD) has been demonstrated. Based on the host-guest inclusion complexation of AZO of the block copolymers and CD cavities on β-CD@QD, they form a hybrid inclusion complex (HIC). The HIC contains a QD as the core and the block copolymer as the shell with the PNIPAM block as the outer layer. Dynamic light scattering (DLS) and UV-vis spectroscopy investigation proved the HIC structure in diluted solution. Hydrogel formed easily upon heating the aqueous solution of HIC at a concentration as low as 7 wt %; as a result of PNIPAM, aggregation occurred above the LCST. The inclusion complex and the domains of the collapsed PNIPAM chains serve as two distinct cross-links and render the hydrogel excellent dual sensitivity to competitive hosts/guests substitution and to temperature variation. Furthermore, rheology results quantitatively exhibit the hydrogel formation mechanism and the sol-to-gel reversibility following the two external stimuli.

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“…Monocamadas auto-organizadas de α e β-ciclodextrinas modificadas com tióis e sulfetos têm sido preparadas para a detecção seletiva de compostos orgânicos [83][84][85][86][87] . Park e colaboradores 88 obtiveram monocamadas de β-ciclodextrinas sobre eletrodos de ouro e estudaram a inclusão de moléculas eletroativas com diferentes dimensões, tais como 2-metil-1,4-naftoquinona, p-benzoquinona e antraquinona.…”

Section: Eletrodos Modificados Com Sam -Análise De Compostos Orgânicosunclassified

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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Supported Monolayers Containing Preformed Binding Sites. Synthesis and Interfacial Binding Properties of a Thiolated .beta.-Cyclodextrin Derivative

Cited by 436 publications

References 0 publications

Metal ion recognition and molecular templating in self-assembled monolayers of cyclic and acyclic polyethers

Metal ion recognition and molecular templating in self-assembled monolayers of cyclic and acyclic polyethers

Dual Stimuli-Responsive Supramolecular Hydrogel Based on Hybrid Inclusion Complex (HIC)

Emprego de monocamadas auto-organizadas no desenvolvimento de sensores eletroquímicos

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