Electrochemical studies of ferrocene derivatives and their complexation by β-cyclodextrin

Coutouli‐Argyropoulou, Evdoxia; Kelaidopoulou, A.; Sideris, C. P.; Kokkinidis, G.

doi:10.1016/s0022-0728(99)00397-6

Cited by 43 publications

(26 citation statements)

References 43 publications

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“…Again, the decrease in the diffusion coefficient of DA can be attributed to the formation of a DA-sulfonated ␤-CD inclusion complex, which has a slower diffusion coefficient due to the large size of the cyclodextrin. This gives a D c /D f ratio of 0.47,which is in very good agreement with ratios found in the literature for the complexation of ferrocenes with ␤-CDs [20,29]. Radi and Eissa [5] also observed a change in the diffusion coeffiecent of Indapamide in the presence and absence of ␤-CD similar to what is shown here.…”

Section: Stoichiometry and Structure Of The Inclusion Complexsupporting

confidence: 91%

“…They explained the positive shift in the oxidation potential and the reduction in the peak oxidation current for ferrocene, which was observed in the presence of the ␤-CD, to the formation of an inclusion complex. Also, Coutouli-Argyropoulou et al [20] reported on the electrochemical properties of derivatives of ferrocencein the presence of ␤-CD. Again, similar shifts in the peak potential for the oxidation of ferrocene derivatives was observed, indicating the formation of the inclusion complex, while Yanez et al [21] obtained similar current and potential data for nifedipine (NF) and nicardipine (NC) in the presence of neutral ␤-CD.…”

Section: Introductionmentioning

confidence: 99%

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An electrochemical study in aqueous solutions on the binding of dopamine to a sulfonated cyclodextrin host

Hendy

Breslin

2012

Electrochimica Acta

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a b s t r a c tClear evidence for the formation of a weak inclusion complex between dopamine (DA) and a sulfonated ␤-CD host in aqueous solution was obtained using a combination of electrochemical approaches. Using cyclic voltammetry, a distinct increase in the oxidation potential of DA and a reduction in the peak oxidation current were observed on adding an excess concentration of the sulfonated ␤-CD to the electrolyte solution. Equally, a clear increase in the half-wave oxidation potential of DA was observed in the presence of the sulfonated ␤-CD using rotating disc voltammetry. The association constant, K, was computed as 331.3 ± 5.8, indicating the formation of a weak inclusion complex, while a 1:1 stoichiometry for the inclusion complex was deduced from a Job's plot analysis. The rate constant for the oxidation of DA was found to decrease on formation of the inclusion complex. This was attributed to higher reorganization energy for the oxidation of the included DA. These changes in the electrochemistry of DA were not observed when an excess of the smaller sulfonated ␣-CD was added to the electrolyte, indicating that these variations are not connected with simple electrostatic interactions between the protonated DA and the anionic sulfonated groups. It is proposed that the aromatic ring of the DA molecule includes within the cyclodextrin cavity, while the protonated amine group remains outside the cavity, bound electrostatically with the anionic sulfonated groups.

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Section: Stoichiometry and Structure Of The Inclusion Complexsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

An electrochemical study in aqueous solutions on the binding of dopamine to a sulfonated cyclodextrin host

Hendy

Breslin

2012

Electrochimica Acta

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“…4(b)). This reduction in the peak current and the anodic shift of the peak potentials for the oxidation of the analyte are consistent with the formation of an inclusion complex [42,43]. The increase in the oxidation potential is connected to the fact that it is more difficult to oxidise the included dopamine, while the decrease in the peak currents is consistent with a lower diffusion coefficient of the included dopamine compared to that of free dopamine.…”

Section: Mechanism Of Sensingsupporting

confidence: 71%

The selective detection of dopamine at a polypyrrole film doped with sulfonated β-cyclodextrins

Harley

Rooney

Breslin

2010

Sensors and Actuators B: Chemical

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a b s t r a c t A highly selective dopamine sensor was fabricated by doping polypyrrole with a sulfonated ␤-cyclodextrin. This composite material enabled the selective sensing of dopamine in the presence of a large excess of ascorbic acid and prevented the regeneration of dopamine through the homogeneous catalytic reaction of the ascorbate anion with the dopamine-o-quinone. A single redox wave, corresponding to the oxidation of dopamine, was observed in dopamine/ascorbate mixtures, giving a truly selective dopamine sensor. The limit of detection was measured as 3.2 × 10 −6 M for dopamine.

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“…6). For our initial construct, the binding constant was determined to be 700 M -1 , which is substantially weaker than the values of 4000-5000 M -1 reported for non-functionalized ferrocene in solution 9 . As both the ferrocene and the cyclodextrin were modified to create the programmable films, the change in the binding constant is not unexpected.…”

Section: Switchable Films For Protein Capturecontrasting

confidence: 61%

“…Respectively, the collected impedance data are fitted to two different equivalent circuits. 8,9 The fitting procedure permits us to determine the barrier layer capacitance (C bl ). The geometric electrode area (A) is estimated to be 1.8 cm 2 and dielectric constant is assumed to be 9.0.…”

Section: Synthesis Of Ferrocene-biotin Compoundsmentioning

confidence: 99%

Integrated nanosystems for monitoring cell-signaling proteins.

Zavadil¹,

Farrow²,

et al. 2007

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Components were developed for an integrated "lab-on-a-chip" that is intended to monitor how single cells respond to external stimuli such as toxins. At the largest length scale (of microns), the system contains a microfluidics platform that can capture single cells, provide them with nutrients, and expose them to toxins. At nanometer length scales, the system contains nanoporous electrodes that can be used to detect the proteins expressed by the captured cells when they are exposed to toxins. Capacitance changes induced on these electrodes can detect as few as four protein molecules per square micron of sensor electrode surface with a dynamic range for protein detection of around three orders of magnitude. At a molecular level, the sensor electrodes are coated with programmable self-assembled monolayers of the molecular host cyclodextrin. This film can be programmed using electrochemical signals to grab or release ferrocene molecules that are functionalized with antibodies. The antibodies are highly selective for adsorbing only those proteins of interest on the sensor surface. While the integration of the films, sensors, and fluidic systems was not completed, it is shown how these components could be used to follow the cell-signaling cascade in white blood cells that is critical to the inner workings of the human immune system. Monitoring the appearance of cytokines and other cellsignaling proteins is relevant to applications ranging from detecting pathogens for Homeland Defense to cellular-level studies that impact human health. 4 ACKNOWLEDGMENTS

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Electrochemical studies of ferrocene derivatives and their complexation by β-cyclodextrin

Cited by 43 publications

References 43 publications

An electrochemical study in aqueous solutions on the binding of dopamine to a sulfonated cyclodextrin host

An electrochemical study in aqueous solutions on the binding of dopamine to a sulfonated cyclodextrin host

The selective detection of dopamine at a polypyrrole film doped with sulfonated β-cyclodextrins

Integrated nanosystems for monitoring cell-signaling proteins.

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