Source:http://linkedlifedata.com/resource/pubmed/id/17521206
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
13
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| pubmed:dateCreated |
2007-6-12
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| pubmed:abstractText |
Monolayers of di-6A,6B-deoxy-6-(4-pyridylmethyl)amino-gamma-cyclodextrin (gamma-CD-(py)2) have been formed on polycrystalline platinum electrodes and investigated using electrochemical and surface-enhanced Raman spectroscopy (SERS). The behavior of self-assembled monolayers of (gamma-CD-(py)2) alone, (gamma-CD-(py)2) backfilled with 1-nonanethiol, and 1-nonanethiol are reported. The potential dependence of the capacitance indicates that the film capacitance is higher for the backfilled CD layers than for 1-nonanethiol layers, most likely due to ion flux through the CD cavity. SERS spectra of the backfilled layer exhibit features associated with both pyridine-functionalized CD and alkane moieties. Investigations using [Fe(CN)6]4- as a solution-phase probe indicate that the backfilled CD-alkane thiol layer exhibits enhanced blocking properties compared to gamma-CD-(py)2 films alone. Complete blocking was achieved by a combination of backfilling and insertion of a high-affinity guest 1-adamantylamine into the cavity. Significantly, an electroactive guest with high affinity for gamma-CD, [Co(biptpy)2]2+, does not exhibit a redox response at the gamma-CD-(py)2 layer but molecular recognition is turned on by backfilling the CD layer with 1-nonanethiol molecules. This switching on of the electrochemical activity suggests that the CD hosts are initially inaccessible but reorientate upon backfilling, exposing the CD opening to solution and permitting a supramolecular host-guest complex to form. The binding of [Co(biptpy)2]2+ to gamma-CD in the backfilled monolayer depends on the bulk concentration of guest and is modeled by the Langmuir isotherm, yielding an association constant for the Co2+ state of 1.45 +/- 0.46 x 105 M-1 and a limiting surface coverage 1.49 +/- 0.25 x 10-11 mol cm-2. The surface coverage of the divalent state is higher than the trivalent state, reflecting the dynamic nature of the inclusion.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
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| pubmed:month |
Jun
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| pubmed:issn |
0743-7463
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:day |
19
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| pubmed:volume |
23
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
6997-7002
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| pubmed:year |
2007
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| pubmed:articleTitle |
Surface-immobilized pyridine-functionalized gamma-cyclodextrin: alkanethiol co-adsorption-induced reorientation.
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| pubmed:affiliation |
National Center for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland.
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| pubmed:publicationType |
Journal Article
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